Ubuntu 8.04 / 8.10 graphics detection changes?

[Tim Gardner]

Zachary Amsden wrote:
> Hi, I'm triaging a VMware related Ubuntu bug where the Ubuntu desktop
> fails to load, and will only run in low-graphics mode if VMI is enabled
> when running in a virtual machine.  Notably, the bug only happens on AMD
> hosts; Intel machines are unaffected.  Also, it does not occur in 8.04,
> but it a regression observed in 8.10.  This leads me to suspect some
> kind of CPUID type detection was added between the two that could
> possibly be misvirtualized when running with paravirtualization.
> 
> Could someone point me to the right place to be looking at how graphics
> mode selection selection might have changed between these two?
> 
> Thanks,
> 
> Zach
> 
> 

Zach,

I implemented a series of patches from Alok Kataria for Hardy (8.04)
that use the LFENCE instruction as a performance improvement alternative
to CPUID. I assume these were carried into 2.6.27, though its hard to
tell with the continued rework if the x86/x86_64 code.

Intrepid is pretty close to stock 2.6.27 in the arch/x86 and kernel
directories. I assume you don't see any issues with vanilla 2.6.27?

rtg
-- 
Tim Gardner tim.gardner at canonical.com