Bug#776911: gnome-shell: fails to start on i386 when [Mesa was] built with llvm-3.5

[Simon McVittie]

Control: unmerge 775235
Control: retitle 775235 gnome-shell: fails to start on i386 when Mesa was built with llvm-3.5
Control: reassign 775235 libgl1-mesa-dri
Control: retitle 770130 gnome-shell: crashes with "Failed to create texture 2d" after "[drm:i8xx_irq_handler] *ERROR* pipe A underrun"

On 09/03/15 20:57, Julien Cristau wrote:
> On Thu, Feb 26, 2015 at 08:54:10 +0000, Simon McVittie wrote:
>> Context for Mesa maintainers: #775235 is that gnome-shell crashes in
>> an i386 VM with its default choice of emulated CPU, with
>> "LLVM ERROR: Do not know how to split the result of this operator!".

I think this should go to Mesa. There are two potential patches,
both tested by Bernhard Übelacker, with 

go back to llvm-3.4:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=775235#15

or apply an unmerged patch:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=775235#32

>> The merged bug #770130 is that gnome-shell crashes on an unknown i386
>> (probably relatively old, since it has 82830M/MG integrated graphics,
>> which Wikipedia says is a Pentium III-M chipset) with
>> "Cogl-ERROR **: Failed to create texture 2d due to size/format constraints".
>> Oddly, this only happens for non-power-of-two textures in the gnome-shell
>> run by the actual user, not by the gnome-shell used for the gdm login
>> prompt (even though both use non-power-of-two textures). Michael Gilbert
>> merged this with #775235 and #776911 without comment; I'm not sure of
>> the reasoning for believing that #775235 and #770130 is the same thing.
>>
>> The other merged bug #776911 is that gnome-shell crashes on an
>> unknown i386 with "Cogl-ERROR **: Failed to create texture 2d due to
>> size/format constraints"; that looks like the same thing as #770130.

I can reproduce symptoms similar to these on a slightly newer machine
(Pentium IV) and have filed an xserver-xorg-video-intel bug with full
logs. These two should maybe be merged with that bug, but I'll leave
that to the X maintainers.

This is on hardware about a decade old, so I don't think it should
realistically be RC: I filed my new bug as "normal".

Regards,
    S