[Dri-devel] xf86-4.2: SIGILL on Celeron b/ 3dnow misdetected?

[Bernhard Kaindl]

Hi,    I'd like to report a finding on my Satellite 1110-z16 with Mobile Celeron 1500 and Radeon LY under SuSE 8.1 and Mandrake 9 using the installed XFree86-4.2 based X11/Mesa.   Both show a problem with many 3D Linux apps arborting with SIGILL, MESA_DEBUG showed that the apps were thinking that the Celeron supported 3DNow(message 3dnow supported was printed) which it at least does not when checking /proc/cpuinfo.   After I disabled the use of 3dnow by exporting MESA_NO_3DNOW, everything works but it's a not good needing to export it and it's only a workaround.   So it looks like as if the Mesa CPUID asm gets the 3dnow feature bit set, so the feature is enabled and depending what the app does it gets the sigill or not(glxgears and fgfs do not but show no rendering in a part of the window if I move another window into the middle of the 3d window.   Both distributions use Free 4.2 code, but I've started downloading the 4.3.99 rpms do test with it.   Just guessing(maybe fixed already, just could not get the newest XF86 4.3/Mesa Source over the slow modem I'm using atm yet, but working on it):   I've checked the 2.4.19 x86 feature/CPUID code in arch/i386/kernel/setup.c and found a place where it does something to the 3dnow flag.   Maybe the CPUID regs set on stepping 7 of the Mobile Celeron 1500 are a bit different and the kernel handles this by the special 3dnow lines I've seen.   Bernd