On Mon, 2002-11-25 at 09:41, Olaf Weber wrote: > > My laptop has a Mobile Pentium 4 processor and Radeon 7500c gfx. I found > that with xlibmesa3 installed and DRI enabled any program that uses OpenGL > would die with a SIGILL in the radeon_dri.so library. > > Investigation revealed that the problem occurred in code containing 3dnow > instructions -- setting MESA_NO_3DNOW prevented the crashes. This in turn > is due to the way the library obtains the capability information for cpus: > it uses CPUID to get the capability bitvectors and passes those around > unchanged. This worked while the bits AMD uses to signal the availability > of 3DNOW were not used by intel as well. In the pentium 4 family, this > assumption no longer holds. > > The code that does the probe is found in > xc/extras/Mesa/src/X86/common_x86_asm.S > > The obvious quick fix would be to mask the problematic bits in the intel > branch of the code before returning the bitvector. A more complete fix > would be to not use the CPU's capability vector directly, but instead use > it to construct a cability vector for the library.
The attached patch is how this was fixed in DRI and XFree86 CVS. -- Earthling Michel D�nzer (MrCooper)/ Debian GNU/Linux (powerpc) developer XFree86 and DRI project member / CS student, Free Software enthusiast
Index: extras/Mesa/src/X86/common_x86_asm.S =================================================================== RCS file: /cvsroot/dri/xc/xc/extras/Mesa/src/X86/common_x86_asm.S,v retrieving revision 1.14 retrieving revision 1.15 diff -p -u -r1.14 -r1.15 --- extras/Mesa/src/X86/common_x86_asm.S 22 Oct 2002 23:38:09 -0000 1.14 +++ extras/Mesa/src/X86/common_x86_asm.S 9 Nov 2002 17:44:32 -0000 1.15 @@ -117,6 +117,11 @@ GLNAME( _mesa_identify_x86_cpu_features MOV_L ( CONST(0x1), EAX ) CPUID MOV_L ( EDX, EAX ) + + /* Mask out highest bit, which is used by AMD for 3dnow + * Newer Intel have this bit set, but do not support 3dnow + */ + AND_L ( CONST(0X7FFFFFFF), EAX) JMP ( LLBL(cpuid_done) ) LLBL(cpuid_amd):
