DRI User Guide
Contents
1. 3 LIBGL_DRIVERS_PATH can be used to override the default directories which are searched for 3D drivers The value is one or more paths separated by colons In a typical XFree86 installation the 3D drivers should be in usr X11R6 lib modules dri and IBGL_DRIVERS_PATH need not be defined Note that this feature is disabled for set uid programs This variable replaces the LIBGL_DRIVERS_DIR env var used in XFree86 4 0 4 MESA_DEBUG if defined will cause Mesa based 3D drivers to print user error messages to stderr These are errors that you d otherwise detect by calling g1GetError Mesa based drivers this includes most of the drivers listed above also observe many of the existing Mesa environment variables These include the MESA_DEBUG and MESA_ INFO variables 9 General Trouble Shooting This section contains information to help you diagnose general problems See below for addi tional information for specific hardware 9 1 Bus Mastering DMA based DRI drivers that s most DRI drivers cannot function unless bus mastering is enabled for your graphics card By default some systems don t having bus mastering on You should enable it in your BIOS Alternately you can check the status of bus mastering and change the setting from within Linux There may be similar procedures for other operating systems Run 1spci as root and find the information describing your graphics adapter For example 00 02. bling the system s fill rate When the second VSA 100 chip is activated glGet String GL_RENDERER will report Voodoo5 instead of Voodoo4 The lowest mipmap level is sometimes miscolored in trilinear sampled polygons The GL_EXT_texture_env_combine extension is supported on the Voodoo4 and Voodoo5 10 1 5 Known Problems The lowest mipmap level is sometimes miscolored in trilinear sampled polygons Voodoo3 Banshee Fog doesn t work with orthographic projections The accuracy of blending operations on Voodoo4 5 isn t always very good If you run Glean you ll find some test failures The Glide library cannot be used directly it s only meant to be used via the tdfx DRI driver SSystem has problems because of poorly set near and far clipping planes The office unc Performer model also suffers from this problem 10 2 Intel i810 10 2 1 Requirements A kernel with AGP GART support such as Linux 2 4 x is needed 10 2 2 Configuration Your XF86Config file s device section must specify the i810 device and specify a usable amount of video ram to reserve Section Device Identifier i810 VendorName Intel Driver i810 Option AGPMode 1 VideoRam 10000 EndSection DRI User Guide The Screen section should then reference the i810 device Section Screen Identifier Screen 1 Device 3910 Monitor High Res Monitor DefaultDepth 16 Subsection Display Depth 16 Modes 1280x1024 1024x768
3. 800x600 640x480 ViewPort 0 0 EndSubsection EndSection The kernel module for the i810 is named i810 0 and should be installed in lib mod ules 2 4 x kernel drivers char drm It will be automatically loaded by the Xserver if needed The DRI 3D driver for the i810 should be in usr X11R6 1ib modules dri i810_dri so This will be automatically loaded by libGL so 10 2 3 Troubleshooting e 3D acceleration for the i810 is only available in the 16 bit pixel screen mode at this time 32bpp acceleration is not supported by this hardware Use xdpyinfo to verify that all your visuals are depth 16 Edit your XF86Config file if needed The i810 uses system ram for video and 3d graphics The X server will ordinarily reserve 4mb of ram for graphics which is too little for an effective 3d setup To tell the driver to use a larger amount specify a VideoRam option in the Device section of your XF86Config file A number between 10000 and 16384 seems adequate for most requirements If too little memory is available for DMA buffers back and depth buffers and textures direct rendering will be disabled 10 2 4 Performance and Features Basically all of the i810 features which can be exposed through OpenGL 1 2 are implemented However the following OpenGL features are implemented in software and will be slow Stencil buffer and accumulation buffer operations Blend subtract min max and logic op blend modes glColorMask when any mask is set to fals
4. DRI User Guide CONTENTS Tt Preamble intensas 1 Al COPYHISDE utilidad rial caladas 1 VZ Trademarks a dd PA tte 1 2 MIO UCAON A A A A So ROS EP OE RR We ie OE RS eT EE 1 3 Supported Architectures amp Hardware o cccccccccscsscssesssesceseteesesceesesesesnenessssseenesesssesseeseseseeenes 2 BA CPU Architectures a A A tt iets Soc 2 3 2 Graphics Hardware ciivoinodioneinidaineno noribiorino sien saute anet ioa EEN Peesi recdtaeioseadba Ra FEOIR aa Fion 2 4 Prerequisite Sottwares finhed i ana a a E E E N A R A 3 5 Kernel Modules lt a A E 3 6 AFS6Contig fle unitat 4 Z Memory usage iieii ON 5 8 Using 3D Acceleration unitat italia 5 Sil DG LASO rd id 5 8 2 Compiling and linking an OpenGL program oocococononononononononononononanonononononononononononananonononoss 5 8 3 Running your OpenGL program onocococononononononononononononononononononononononononononononononononononananonenanons 5 8 4 dibOSMesaiso nr A E es ee 6 8 5 BIXINEO S sonegis e a Aa a ap araa irae aE A E ini 6 8 6 Environment Variables ooonnnccnincccccnnncnnnonaninnancnnnnananonononnnncranona S a E a S ar 6 9 General Trouble Shooting isre ipt ia e oaiae EASE i Se EEEE EAEE EE ESE 7 91r Bus Mastering viserne i eree tI eate sean a AeA R aa aE R ee ae Ke AE a eea aie Eien Eea Tin 7 92 VHC IX Server E E RAN 8 9 3 Linking running and verifying 3D acceleration oooncocononenoncnnnnnnonnnnnnnnnnannnannnnrnanirarannaninanass 9 10 Hardware Specific In
5. bash dev 01 00 0 change as appropriate echo Enabling bus mastering on device dev setpci s dev 4 w printf x 0x setpci s dev 4 w 4 dev 00 00 0 echo Enabling bus mastering on host bridge dev setpci s dev 4 w printf x 0x setpci s dev 4 w 4 DRI User Guide You can check if this worked by running the first setpci command again 9 2 The X Server 1 Before you start the X server verify the appropriate 3D kernel module is installed Type lsmod and look for the appropriate kernel module For 3dfx hardware you should see tdfx for example Verify you re running XFree86 4 0 or newer and not an older version If you run xdpy info and look for the following line near the top vendor release number 4000 Verify that your XF86Config file usually found at etc X11 XF86Config loads the glx and dri modules and has a DRI section See the Software Resources section below for sample XF86Config files Examine the messages printed during X server startup and check that the DRM module loaded Using the Voodoo3 as an example TDFX 0 Write combining range 0xf0000000 0x2000000 II TDFX 0 Textures Memory 7 93 MB 0 drm created tdfx driver at busid PCI 1 0 0 0 drm added 4096 byte SAREA at 0xc65dd000 0 drm mapped SAREA Oxc65dd000 to 0x40013000 0 drm framebuffer handle 0xf0000000 0 drm added 1 reserved context for kernel II TDFX 0 drm Registers 0xfc00000
6. problems which may occur Readers should have a basic understanding of Linux X and OpenGL See the resources section at the end for more documentation and software downloads This document does not cover compilation or installation of XFree86 4 x It is assumed that you ve already installed a Linux distribution which includes XFree86 4 x or that you re an experi enced Linux developer who has compiled the DRI for himself DRI download compilation and installation instructions can be found at http dri sourceforge net DRIcompile html Edits corrections and updates to this document may be mailed to DRI User Guide DRI User Guide lt brian tungstengrahpics com gt 3 Supported Architectures amp Hardware 3 1 CPU Architectures The architectures currently supported by the DRI have grown from the initial Intel i386 systems to now include the Alpha Processor and the Sun SPARC machines Intel s SSE a k a Katmai instructions are used in optimized vertex transformation functions in Mesa based drivers This requires a recent Linux kernel both at compile and runtime See the DRI Compile Guide for compile time requirements At runtime a check is made to determine if the CPU can execute SSE instructions They re disabled otherwise AMD s 3DNow instructions are also used in optimized vertex transformation functions in the Mesa based DRI drivers 3DNow is supported in most versions of Linux Like the SSE opti mizations a runtime check
7. with the MGA driver being very sluggish when the DRI is enabled to the point of being unusable This is caused by the graphics card not having an inter rupt assigned to it The current DRI trunk will attempt to detect this condition and bail out grace fully The solution to the above problem is to assign an interrupt to your graphics card This is some thing you must turn on in your system BIOS configuration Please consult your system BIOS manual for instructions on how to enable an interrupt for your graphics card 10 3 5 MGA HAL lib MGAHALlib a is a binary library Matrox has provided for use under Linux to expose functional ity for which they can not provide documentation For example TV Out requires MacroVision be enabled on the output This binary library also sets the pixel memory clocks to the optimal set tings for your Matrox card Currently the MGAHAL library is required for the G450 to work You can download this from the driver section on Matrox s website www matrox com mga Here modifications to the DRI build instructions which make the mga ddx driver use the MGA HAL library 1 Put the following define in your host def file define UseMatroxHal YES 2 Place mgaHALlib a in the following directory xc programs Xserver hw xfree86 drivers mga HALlib You can use DualHead on the G400 G450 DH cards by creating two device sections which both point to the same BusID For most AGP devices the BusID will be PCI 1 0 0 Config
8. 0 II TDFX 0 visual configs initialized II TDFX 0 Using XFree86 Acceleration Architecture XAA Screen to screen bit blits Solid filled rectangles 8x8 mono pattern filled rectangles Indirect CPU to Screen color expansion Solid Lines Dashed Lines Offscreen Pixmaps Driver provided NonTEGlyphRenderer replacement Setting up tile and stipple cache 10 128x128 slots TDFX 0 Backing store disabled TDFX 0 Silken mouse enabled 0 X context handle 0x00000001 0 drm installed DRM signal handler 0 DRI installation complete II TDFX 0 direct rendering enabled 5 After the X server has started verify that the required X server extensions are loaded Run xdpy info and look for the following entries in the extensions list GLX SGI GLX XFree86 DRI DRI User Guide 9 3 Linking running and verifying 3D acceleration After you ve verified that the X server and DRI have started correctly it s time to verify that the GL library and hardware drivers are working correctly 1 Verify that you re using the correct libGL so library with ldd The usr lib and usr X11R6 lib directories are expected locations for libGL so Example ldd usr local bin glxinfo libglut so 3 gt usr local lib libglut so 3 0x40019000 libGLU so 1 gt usr local lib libGLU so 1 0x40051000 libGL so 1 gt usr lib libGL so 1 0x40076000 libXmu so 6 gt usr X11R6 lib libXmu so 6 0x402ee000 libXi so 6 gt usr X11
9. 0 0 Host bridge Intel Corporation 440BX ZX 82443BX ZX Host bridge rev 03 00 01 0 PCI bridge Intel Corporation 440BX ZX 82443BX ZX AGP bridge rev 03 00 07 0 ISA bridge Intel Corporation 82371AB PIIX4 ISA rev 02 00 07 1 IDE interface Intel Corporation 82371AB PIIX4 IDE rev 01 00 07 2 USB Controller Intel Corporation 82371AB PIIX4 USB rev 01 00 07 3 Bridge Intel Corporation 82371AB PIIX4 ACPI rev 02 00 11 0 Ethernet controller Intel Corporation 82557 Ethernet Pro 100 rev 08 00 12 0 SCSI storage controller Symbios Logic Inc formerly NCR 53c895 rev 02 00 14 0 Multimedia audio controller Ensoniq ES1371 AudioPCI 97 rev 08 01 00 0 VGA compatible controller 3Dfx Interactive Inc Unknown device 0009 rev 01 The bus device and function number comprise the device id which is conventionally written in the form bus dev func or in this case 01 00 0 Use the setpci command to examine bit two of register 4 for your graphics card This will indi cate whether or not bus mastering is enabled setpci s 01 00 0 4 w A hexadecimal value will be printed Convert the least significant digit to binary For example if you see 3 that s 0011 in binary bit two is 0 If you see 7 that s 0111 in binary bit two is 1 In the first example bus mastering is disabled It s enabled in the second example The following shell script will enabled bus mastering for your graphics card and host bridge Run it as root bin
10. 24 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection EndSection The kernel module for the Radeon is named radeon o and should be installed in lib mod ules 2 4 x kernel drivers char drm It will be automatically loaded by the Xserver if needed The DRI 3D driver for the Radeon should be in usr X11R6 lib mod ules dri radeon_dri so This will be automatically loaded by libGL so You may also set your screen depth to 32 for 32bpp mode 10 5 3 Performance and Features While this driver supports many of the features of ATI Radeon cards we do not yet fully support the card s TCL features This work is progressing but is not yet ready The AGP mode may be set to 1 2 or 4 One is used by default Higher AGP speeds may result in unreliable performance depending on your motherboard The following OpenGL features are implemented in software and will be slow DRI User Guide e Blend subtract blend min max and blend logicops e Stencil and accumulation operations e 1D and 3D textures e Texture borders The GL_EXT_texture_env_combine GL_EXT_texture_env_add and GL_EXT_texture_env_dot3 extensions are supported or will be soon supported in the new driver based on Mesa 3 5 We hope to implement support for the following features in the future e Vertex transformation clipping and lighting TCL e Hardware stencil buffer e Cube map textures e 3D textures e Three texture units 10 5 4 Known Problems Certai
11. DRI User Guide FLOP IN DRI User Guide VA Linux Systems Inc Professional Services Graphics 15 June 2001 1 Preamble 1 1 Copyright Copyright 2000 2001 by VA Linux Systems Inc All Rights Reserved Permission is granted to make and distribute verbatim copies of this document provided the copyright notice and this permission notice are preserved on all copies 1 2 Trademarks OpenGL is a registered trademark and SGI is a trademark of Silicon Graphics Inc Unix is a reg istered trademark of The Open Group The X device and X Window System are trademarks of The Open Group XFree86 is a trademark of The XFree86 Project Linux is a registered trademark of Linus Torvalds Intel is a registered trademark of Intel Corporation 3Dlabs GLINT and Oxy gen are either registered trademarks or trademarks of 3Dlabs Inc Ltd 3dfx Voodoo3 Voodoo4 and Voodoo are registered trademarks of 3dfx Interactive Incorporated Matrox is a registered trademark of Matrox Electronic Systems Ltd ATI Rage and Radeon are registered trademarks of ATI Technologies Inc All other trademarks mentioned are the property of their respective own ers 2 Introduction With XFree86 4 x and the Direct Rendering Interface DRI hardware accelerated 3D graphics can be considered a standard feature on Linux workstations Support for other operating systems such as FreeBSD is underway This document describes how to use the DRI system and troubleshoot
12. R6 1ib 1ibXi so 6 0x40301000 libm so 6 gt lib libm so 6 0x40309000 libc so 6 gt lib libc so 6 0x40325000 libX11 so 6 gt usr X11R6 1ib 1ibX11 s0o 6 0x40419000 libXt so 6 gt usr X11R6 1ib 1libXt so 6 0x404bd000 libSM so 6 gt usr X11R6 lib 1ibSM so 6 0x40509000 libICE so 6 gt usr X11R6 1ib 1ibICE so 6 0x40512000 libXext so 6 gt usr X11R6 1ib libXext so 6 0x40529000 libvga so 1 gt usr lib libvga so 1 0x40537000 libpthread so 0 gt lib libpthread so 0 0x4057d000 lib ld linux so 2 gt lib 1ld linux so 2 0x40000000 2 You may also double check that libGL so is in fact DRI capable Run strings libGL so 1 2 grep DRI and look for symbols prefixed with XF86DRI such as XF86DRIQueryExtension 3 To be safe one should run ldconfig after installing libGL so to be sure the runtime loader will find the proper library 4 Verify that the appropriate 3D driver is in usr X11R6 lib modules dri For example the 3dfx driver will be named tdfx_dri so 5 Set the LIBGL_DEBUG environment variable This will cause libGL so to print an error message if it fails to load a DRI driver Any error message printed should be self explana tory 6 Run glxinfo Note the line labeled OpenGL renderer string It should have a value which starts with Mesa DRI followed by the name of your hardware 7 Older Linux OpenGL applications may have been linked against Mesa s GL library and will not automa
13. e GL_SEPARATE_SPECULAR_COLOR lighting mode glDrawBuffer GL_FRONT_AND_BACK Using 1D or 3D textures Using texture borders 10 3 Matrox G200 and G400 10 3 1 Requirements A kernel with AGP GART support such as Linux 2 4 x is needed 10 3 2 Configuration Your XF86Config file s device section must specify the mga device DRI User Guide Section Device Identifier MGA VendorName Matrox Driver mga Option AGPMode 1 VideoRam 32768 EndSection The Screen section should then reference the MGA device Section Screen Identifier Screen 1 Device MGA Monitor High Res Monitor DefaultDepth 16 Subsection Display Depth 16 Modes 1280x1024 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection EndSection To use a 32bpp screen mode use this Screen section instead Section Screen Identifier Screen 1 Device MGA Monitor High Res Monitor DefaultDepth 24 DefaultFbBpp 32 Subsection Display Depth 24 Modes 1280x1024 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection EndSection The kernel module for the G200 G400 is named mga o and should be installed in lib mod ules 2 4 x kernel drivers char drm It will be automatically loaded by the Xserver if needed The DRI 3D driver for the G200 G400 should be in usr X11R6 lib mod ules dri mga_dri so This will be automatically loaded by libGL so 10 3 3 Performance and Features Software rendering will be used under any of
14. e following DRI section Section DRI Group xf86dri Mode 0660 EndSection This would limit access to direct rendering to those users in the x 86dri group fred and jane in this example When other users tried to use direct rendering they would fall back to unaccel erated indirect rendering Note that there is a known bug in XFree86 4 0 that prevents some changes to the DRI section DRI User Guide from taking effect Until this bug is fixed if you change the DRI section please also remove the dev dri directory with the rm rf dev dri command Finally the XF86Config file needs Device and Screen sections specific to your hardware Look in section 10 Hardware Specific Information and Troubleshooting for details 7 Memory usage Using the 3D features of a graphics card requires more memory than when it s just used as a 2D device Double buffering depth buffering stencil buffers textures etc all require extra graphics memory These features may require four times the memory used for a simple 2D display If your graphics card doesn t have a lot of memory less than 16MB for example you may have to reduce your screen size and or color depth in order to use 3D features Reducing the screen resolution will also leave more space for texture images possibly improving 3D performance If for example you play Quake3 at 1024x768 but start your display at 1600x1200 you might con sider restarting X at 1024x768 in order to max
15. formation and Troubleshooting ccicicicicocicinanininanininnanacaninanonanananananananeno 10 10 1 3dfx Banshee Voodoo3 Voodoo4 and Voodoo5 Series ccsccsccccsscssscessseesscesseeesseeseeeeees 10 IO Titel aS lO vidal 12 10 3 Matrox G200 and G400 a e ode dbs a el a A bbs 13 10 4 ATI Rage 128 unan ibi iii 15 105 ATT Radeon daa bios 17 10 6 3DLabs Oxygen GMX 2000 cnica reee aereas 18 11 General Limitations and Known Bugs eoccccccicocinoncncnnnnanananonananencnanananananonananananananonononananonananananens 18 A O A O ROT 18 A A 18 WS Debugging o srei renta ni anton DAI oops 18 IA chests dea piia gnaire chads E Eein E aAA eE E RE A a Ea 19 Hb GbGLE soand dopen carnicero sins 19 11 6 Bug Database Mini iaa NEE E AE E EE 19 12 RESOULCES a A AA A A A A ts entitle tab 19 ARMAS A e e al e e ao e 19 12 2 DOCUMENTATION stat 19 129 SUpport ranita inicia sianiasi cir 20 XFree86 xc programs Xserver hw xfree86 doc sgml DRI sgml v 1 29 2003 02 17 03 57 29 dawes Exp
16. imize your texture memory space The documentation included with your card should have information about maximum screen size when using 3D 8 Using 3D Acceleration This section describes how to link your application with libGL so and verify that you are in fact using 3D acceleration 8 1 libGL so Your OpenGL program must link with the libGL so 1 2 library provided by XFree86 The libGL so 1 2 library contains a GLX protocol encoder for indirect remote rendering and DRI code for accessing hardware drivers In particular be sure you re not using libGL so from another source such as Mesa or the Utah GLX project Unless it was built in a special way the libGL so library does not contain any 3D hardware driver code Instead libGL so dynamically loads the appropriate 3D driver during initialization Most simple OpenGL programs also use the GLUT and GLU libraries A source for these libraries is listed in the Resources section below 8 2 Compiling and linking an OpenGL program A simple GLUT OpenGL program may be compiled and linked as follows gcc program c I usr local include L usr local lib L usr X11R6 lib lglut 1GLU 1GL o progran The I option is used to specify where the GL glut h and possibly the GL gl h and GL glu h header file may be found The L options specify where the libglut so and the X libraries are located libGL so and libGLU so should be in usr lib as specified by the Linux OpenGL ABI standard The 1gl
17. is made to determine if the CPU can execute 3DNow instructions Alpha based systems can use Compaq s optimized math library for improved 3D performance See the DRI Compilation Guide for details 3 2 Graphics Hardware XFree86 4 2 or later versions includes 3D acceleration for the following graphics hardware e 3dfx supported on Intel x86 AMD and Alpha Voodoo5 5500 Voodoo4 4500 Voodoo3 3500 TV Voodoo3 3000 AGP Voodoo3 3000 PCI Voodoo3 2000 AGP Voodoo3 2000 PCI Voodoo Banshee Velocity 100 200 There are many configurations of 3dfx cards on the market Not all have been tested e Matrox supported on Intel x86 and AMD e Matrox G200 e Matrox G400 e Intel i810 i815 i830 motherboard chipsets e i810 i810 dc100 1810e e 1815 e 1830 DRI User Guide ATI Rage 128 supported on Intel x86 AMD and Alpha Rage Fury Rage Magnum XPERT 2000 XPERT 128 XPERT 99 All in Wonder 128 Rage 128 PCI Alpha based systems Note that both PCI and AGP versions of Rage 128 based cards are supported at this time ATI Radeon supported on Intel x86 AMD and Alpha Radeon SDR AGP Radeon DDR AGP Radeon 32MB SDR PCI Alpha based systems Radeon 7000 M6 RV100 Radeon 7200 R100 Radeon 7500 M7 RV200 Radeon 8500 9100 R200 Radeon 9000 M9 RV250 3Dlabs supported on Intel x86 and AMD e Oxygen GMX 2000 MX Gamma based Note this driver is no longer being actively developed Support for other hardware
18. is underway Most of the DRI development work is funded by con tracts with IHVs These contracts often prevent us from announcing drivers before they re released Queries about upcoming drivers may not be answerable 4 Prerequisite Software The DRI is available in XFree86 4 0 and later e Some hardware drivers require specific versions of the Linux kernel for AGP support etc See section 10 for specifics e You DO NOT need to install Mesa separately The parts of Mesa needed for hardware acceleration are already in the XFree86 DRI project 5 Kernel Modules 3D hardware acceleration requires a DRI kernel module that s specific to your graphics hardware The DRI kernel module version must exactly match your running kernel version Since there are so many versions of the kernel it s difficult to provide precompiled kernel modules While the Linux source tree includes the DRI kernel module sources the latest DRI kernel sources will be found in the DRI source tree See the DRI Compilation Guide for information on compiling the DRI kernel modules DRI User Guide XFree86 4 0 1 added automatic kernel module loading to the X server On Linux the X server uses modprobe to load kernel modules In Linux 2 4 x the DRM kernel modules should be kept in lib modules 2 4 x kernel drivers char drm for automatic loading to work Optionally DRM kernel modules can be loaded manually with insmod prior to starting the X server You can verify
19. like this OpenGL vendor string VA Linux Systems Inc OpenGL renderer string Mesa DRI Voodoo3 20000224 OpenGL version string 1 2 Mesa 3 4 or this OpenGL vendor string VA Linux Systems Inc OpenGL renderer string Mesa GLX Indirect OpenGL version string 1 2 Mesa 3 4 The first example indicates that the 3dfx driver is using Voodoo3 hardware The second example indicates that no hardware driver was found and indirect unaccelerated rendering is being used If you see that indirect rendering is being used when direct rendering was expected proceed to the troubleshooting section glxinfo also lists all of the GLX enhanced visuals available so you can determine which visuals are double bufferd have depth Z buffers stencil buffers accumulation buffers etc 8 6 Environment Variables The libGL so library recognizes three environment variables Normally none of them need to be defined If you re using the csh or tcsh shells type setenv VARNAME value to set the variable Otherwise if you re using sh or bash type export VARNAME value 1 LIBGL_DEBUG if defined will cause libGL so to print error and diagnostic messages This can help to solve problems Setting LIBGL_DEBUG to verbose may provide additional information 2 LIBGL_ALWAYS_INDIRECT if defined this will force libGL so to always use indirect ren dering instead of hardware acceleration This can be useful to isolate rendering errors DRI User Guide
20. ll not perform as well as their AGP counterparts For AGP cards the AGP mode may be set to 1 2 or 4 One is used by default Higher AGP speeds may result in unreliable performance depending on your motherboard Note that even at 32bpp there is no alpha channel The following OpenGL features are implemented in software and will be slow e accumulation buffer operations e stencil when using a 16bpp screen e Blend subtract min max and logic op blend modes e GL_SEPARATE_SPECULAR_COLOR lighting mode DRI User Guide e glDrawBuffer GL_FRONT_AND_BACK Using 1D or 3D textures e Using texture borders 10 4 4 Known Problems If you experience stability problems you may try setting the UseCCEFor2D option to true This will effectively disable 2D hardware acceleration Performance will be degraded of course 10 5 ATI Radeon 10 5 1 Requirements A kernel with AGP GART support such as Linux 2 4 x is needed 10 5 2 Configuration Your XF86Config file s device section must specify the at i device Section Device Identifier Radeon VendorName ATI Driver tati Option AGPMode 1 EndSection The Screen section should then reference the Radeon device Section Screen Identifier Screen 1 Device Radeon Monitor High Res Monitor DefaultDepth 16 Subsection Display Depth 16 Modes 1280x1024 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection Subsection Display Depth 32 Modes 1280x10
21. n early revisions of the AMD Irongate chipset have AGPGART problems which effect Radeon and other graphics cards The card may work unreliably or not work at all If the DRM kernel module is not loaded the 2D Xserver may work There s hope that this can be fixed in the future 10 6 3DLabs Oxygen GMX 2000 The driver for this hardware was experimental and is no longer being developed or supported 11 General Limitations and Known Bugs 11 1 OpenGL The following OpenGL features are not supported at this time overlays stereo hardware acceler ated indirect rendering OpenGL like functionality is provided with the Mesa library XFree86 4 1 0 uses Mesa 3 4 2 Sub sequent releases of XFree86 will use newer versions of Mesa When newer versions of Mesa are available the 3D drivers can be updated without reinstalling XFree86 or libGL so 11 2 GLX The GLX 1 3 API is exported but none of the new 1 3 functions are operational The new g1XGetProcAddressARB function is fully supported GLXPixmap rendering is only supported for indirect rendering contexts This is a common OpenGL limitation Attempting to use a direct rendering context with a GLXPixmap will result in an X protocol error 11 3 Debugging Debugging DRI drivers with gdb can be difficult because of the locking involved When debug ging OpenGL applications you should avoid stepping inside the GL functions If you re trying to debug a DRI driver it s recommended that you d
22. o so remotely from a second system DRI User Guide 11 4 Scheduling When you run multiple GL applications at once you may notice poor time slicing This is due to an interaction problem with the Linux scheduler which will be addressed in the future 11 5 libGL so and dlopen A number of popular OpenGL applications on Linux such as Quake3 Hereticll Heavy Gear 2 etc dynamically open the libGL so library at runtime with dlopen rather than linking with IGL at compile link time If dynamic loading of libGL so is not implemented carefully there can be a number of serious problems Here are the things to be careful of in your application e Specify the RTLD_GLOBAL flag to dlopen If you don t do this then you ll likely see a runtime error message complaining that _glapi_Context is undefined when libGL so tries to open a hardware specific driver Without this flag nested opening of dynamic libraries does not work Do not close the library with dlclose until after XCloseDisplay has been called When libGL so initializes itself it registers several callbacks functions with Xlib When XCloseDis play is called those callback functions are called If libGL so has already been unloaded with dlclose this will cause a segmentation fault Your application should link with lpthread On Linux libGL so uses the pthreads library in order to provide thread safety There is apparently a bug in the dlopen dlclose code which causes c
23. o to verify that all your visuals are depth 16 Edit your XF86Config file if needed The dev 3d x device is not used for DRI it s only for Glide on older 3dfx hardware Different versions of Glide are needed for Voodoo3 and Voodoo5 See the DRI website s resources page to download the right version of Glide Voodoo4 5 may be run at 24bpp instead of 32bpp the default but 3D acceleration is not supported in that mode 32bpp mode is fully 3D accelerated 10 1 4 Performance and Features Normally buffer swapping in double buffered applications is synchronized to your moni tor s refresh rate This may be overridden by setting the FX_GLIDE_SWAP INTERVAL envi ronment variable The value of this variable indicates the maximum number of swap buffer commands can be buffered Zero allows maximum frame rate On Voodoo4 5 rendering with 16 bits texel textures is faster than using 32 bit per texel textures The internalFormat parameter to gl1TexImage2D can be used to control texel size Quake3 and other games let you control this as well The glTexEnv mode GL_BLEND is not directly supported by the Voodoo3 hardware It can be accomplished with a multipass algorithm but it s not implemented at this time Applica tions which use that mode such as the Performer Town demo may become sluggish when falling back to software rendering to render in that mode The Voodoo3 Banshee driver reverts to software rendering under the following condition
24. rashes if the library uses pthreads but the parent application doesn t The only known work around is to link the application with lpthread Some applications don t yet incorporate these procedures and may fail For example changing the graphics settings in some video games will expose this problem The DRI developers are working with game vendors to prevent this problem in the future 11 6 Bug Database The DRI bug database which includes bugs related to specific drivers is at the SourceForge DRI Bug Database Please scan both the open and closed bug lists to determine if your problem has already been reported and perhaps fixed 12 Resources 12 1 Software A collection of useful configuration files libraries headers utilities and demo programs is avail able from http dri sourceforge net res phtml 12 2 Documentation General OpenGL information is available at the OpenGL Home Page XFree86 information is available at the XFree86 Home Page Information about the design of the DRI is available from Precision Insight Inc Visit the DRI project on SourceForge net for the latest development news about the DRI and 3D drivers The DRI Compilation Guide explains how to download compile and install the DRI for yourself DRI User Guide 12 3 Support The DRI users mailing list at SourceForge is a forum for people to discuss DRI problems In the future there may be IHV and Linux vendor support resources for the DRI
25. s Setting GL_LIGHT_MODEL_COLOR_CONTROL to GL_SEPARATE_SPECULAR_COLOR e Enabling line stippling or polygon stippling e Enabling point smoothing or polygon smoothing Enabling line smoothing when line width is not 1 0 That is antialiased lines are done in hardware only when the line width is 1 0 e Using 1 D or 3 D texture maps Using the GL_BLEND texture environment glide grSstSele DRI User Guide sing stencil operations sing the accumulation buffer sing gl1BlendEquation GL_LOGIC_OP sing glPolygonMode face GL_POINT or glPolygonMode face U U U Using glDrawBuffer GL_FRONT_AND_BACK U GL_LINE U sing point size attenuation i e GL_DISTANCE_ATTENUATION_EXT e Using glColorMask r g b a whenr g or g b The Voodoo5 driver reverts to software rendering under the same conditions Voodoo3 with three exceptions First stencil operations are implemented in hardware when the screen is configured for 32 bits pixel Second the GL_BLEND texture env mode is fully supported in hardware Third ylColorMask is fully supported in hardware when the screen is config ured for 32 bits pixel As of January 2001 the second VSA 100 chip on the Voodoo5 is not yet operational There fore the board isn t being used to its full capacity The second VSA 100 chip will allow Scan Line Interleave SLI mode for full screen applications and games potentially dou
26. that the kernel module was installed with lsmod checking the X server startup log and checking that proc dri 0 exists 6 XF86Config file The XFree86 configuration file is usually found in etc X11 XF86Config This section describes the parts which must be specially set for the DRI First the XF86Config file must load the GLX and DRI modules Section Module This loads the GLX module Load glx This loads the DRI module Load dari EndSection Next the DRI section can be used to restrict access to direct rendering A client can only use direct rendering if it has permission to open the dev dri card file s The permissions on these DRI device files is controlled by the DRI section in the XF86Config file If you want all of the users on your system to be able to use direct rendering then use a simple DRI section like this Section DRI Mode 0666 EndSection This section will allow any user with a current connection to the X server to use direct rendering If you want to restrict the use of direct rendering to a certain group of users then create a group for those users by editing the etc group file on your system For example you may want to create a group called xf86dri and place two users e g fred and jane in that group To do that you might add the following line to etc group xf86dri x 8000 fred jane You have to be careful that the group id 8000 in this example is unique Then you would use th
27. the following conditions Using glDrawBuffer GL_FRONT_AND_BACK U U sing point line or triangle smoothing sing glLogicOp sing glPolygonStipple or glLineStipple U Using 1D or 3D textures e Using texture borders Using glDepthFunc GL_NEVER DRI User Guide e Using the accumulation buffer The AGP mode may be set to 1 2 or 4 One is used by default Higher AGP speeds may result in unreliable performance depending on your motherboard Compaq has funded the implementation of AGP accelerated ReadPixels and DrawPixels in this driver With this implementation on a G400 drawing directly from AGP memory exported to the client throughput of up to 1 GB sec has been measured Additionally Compaq s funding has produced several new extensions in Mesa including one packed_depth_stencil_ MESA which enables Read DrawPixels functionality to operate directly on the packed 24 8 depth stencil buffers of this hardware In order to access this functionality the application must ensure that all pixel processing opera tions are disabled There are in addition a fairly complex set of rules regarding which pack ing unpacking modes must be used and which data formats are supported and alignment con straints See the files in lib GL mesa src drv mga DOCS for a summary of these The exten sion definitions are included in the Mesa 3 4 source distribution 10 3 4 IRQ Assignment There have been problems in the past
28. tically use libGL so In some cases making symbolic links from the Mesa GL library to libGL so 1 will solve the problem ln s libGL so 1 libMesaGL so 3 In other cases the application will have to be relinked against the new XFree86 libGL so It is reported that part of the problem is that running ldconfig will silently rewrite sym bolic links based on the SONAME field in libraries If you re still having trouble look in the next section for information specific to your graphics card DRI User Guide 10 Hardware Specific Information and Troubleshooting This section presents hardware specific information for normal use and troubleshooting 10 1 3dfx Banshee Voodoo3 Voodoo4 and Voodoo5 Series 10 1 1 Requirements The 3dfx DRI driver requires special versions of the 3dfx Glide library Different versions of Glide are needed for Banshee Voodoo3 than for Voodoo4 5 The Glide libraries can be down loaded from the DRI website 10 1 2 Configuration Your XF86Config file s device section must specify the tafx device For example Device Identifier Section VendorName Driver EndSection Device Identifier Section VendorName Driver EndSection Voodoo3 3dfx tdfx Voodoo5 3dfx Cars The Screen section should then reference the Voodoo device Section Screen Identifier Screen 1 Device Voodoo3 Monitor High Res Monitor DefaultDepth 16 Subsection Display Depth 16 Modes 1280
29. ure your screen section as you would normally configure XFree86 4 x Multihead It should be noted that currently the second head does not support direct rendering 10 3 6 Known Problems None 10 4 ATI Rage 128 DRI User Guide 10 4 1 Requirements A kernel with AGP GART support such as Linux 2 4 x is needed 10 4 2 Configuration Your XF86Config file s device section must specify the at i device Section Device Identifier Ragel28 VendorName ATI Driver ati Option AGPMode 1 Option UseCCEFor2D false EndSection The Screen section should then reference the Rage 128 device Section Screen Identifier Screen 1 Device Rage128 Monitor High Res Monitor DefaultDepth 16 Subsection Display Depth 16 Modes 1280x1024 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection Subsection Display Depth 32 Modes 1280x1024 1024x768 800x600 640x480 ViewPort 0 0 EndSubsection EndSection The kernel module for the Rage 128 is named r128 0 and should be installed in lib mod ules 2 4 x kernel drivers char drm It will be automatically loaded by the Xserver if needed The DRI 3D driver for the Rage 128 should be in usr X11R6 lib mod ules dri r128_dri so This will be automatically loaded by libGL so You may also set your screen depth to 32 for 32bpp mode 10 4 3 Performance and Features While PCI Rage 128 based cards are supported they do not yet support PCI GART so they wi
30. ut 1GLU 1GL arguments specify that the application should link with the GLUT GLU and GL libraries in that order 8 3 Running your OpenGL program Simply typing program in your shell should execute the program If you get an error message such as DRI User Guide gears error in loading shared libraries libGL so 1 cannot open shared object file No such file or directory if means that the libGL so 1 file is not the right location Proceed to the trouble shooting section 8 4 libOSMesa so OSMesa Off Screen Mesa is an interface and driver for rendering 3D images into a user allo cated block of memory rather than an on screen window It was originally developed for Mesa before Mesa became part of the XFree86 DRI project It can now be used with the XFree86 DRI libGL so as well libOSMesa so implements the OSMesa interface and it must be linked with your application if you want to use the OSMesa functions You must also link with libGL so For example gcc osdemo c 1OSMesa 1GLU 1GL o osdemo In stand alone Mesa this interface was compiled into the monolithic libGL so formerly libMe saGL so library In XFree86 4 0 1 and later this interface is implemented in a separate library 8 5 glxinfo glxinfo is a useful program for checking which version of libGL you re using as well as which DRI based driver Simply type glxinfo and examine the OpenGL vendor renderer and version lines Among the output you should see something
31. x1024 1024x768 800x600 ViewPort 0 0 EndSubsection EndSection Or Section Screen Identifier Screen 1 Device Voodoo5 Monitor High Res Monitor DefaultDepth 24 Subsection Display Depth 16 Modes 1280x1024 1024x768 800x600 ViewPort 0 0 EndSubsection Subsection Display Depth 24 Modes 1280x1024 1024x768 800x600 ViewPort 0 0 EndSubsection EndSection 640x480 640x480 640x480 DRI User Guide The kernel module for 3dfx hardware is named tdfx o and should be installed in lib mod ules 2 4 x kernel drivers char drm It will be automatically loaded by the Xserver if needed The DRI 3D driver for 3dfx hardware should be in usr X11R6 lib mod ules dri tdfx_dri so This will be automatically loaded by libGL so The Voodoo5 supports 3D rendering in 16 and 32 bpp modes When running in 32bpp mode an 8 bit stencil buffer and 24 bit Z depth buffer are offered When running in 16bpp mode only a 16 bit Z depth buffer is offered and stencil is implemented in software A software based accumulation buffer is available in both 16 and 32bpp modes 10 1 3 Troubleshooting If you try to run an OpenGL application and see an error message similar to gd error glide gd error glide grSstSelect non existent SSTgd error it means that you have the wrong version of the Glide library for your hardware 3D acceleration for Banshee and Voodoo3 is only supported in the 16 bit pixel screen mode Use xdpyinf
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