GCC4 and volatile effects on xorg-x11

[Thomas Winischhofer]

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Lonni J Friedman wrote:
> On 7/17/05, Jim Cornette <jim-cornette at insight.rr.com> wrote:
> 
>>Hi,
>>I am new to the list and could not find discussions from the last two
>>months on GCC4 optimizations which cause misbehaving xorg-x11 servers on
>>various cards. The problems seem to effect Intel, MGA, cyberblade and
>>varous other drivers. Replacing the libvgahw.a file with a version
>>compiled for a previous distribution of Fedora Core 3 will get X up and
>>running again. Recent tests show that using lesser optimization will
>>allow X to work on a larger amount of hardware, but not all hardware is
>>made to work again with gcc4 and reduced optimization.
>>
>>A thread on the gcc list that refers to this problem is listed below.
>>
>>http://gcc.gnu.org/ml/gcc/2005-07/msg00699.html
>>
>>I use the compiled binaries from distributions mostly. I do not know a
>>lot about coding. I think people are working on resolving the changes
>>which caused the many failures with X on certain hardware.
>>
>>Ny troubles are with an Intel 815 displaying a blue border with wrapped
>>text when changing to a virtual terminal. On an Intel 865G, the
>>terminals are blank. Changing the libvgahw.a fixes both issues. Using
>>lessor compilation errors fixes the Intel 815 but not the Intel 865G.
>>
>>X seems to work great in the GUI. The problem is with the virtual terminals.
>>
> 
> 
> FWIW, I'm also seeing identical behavior here with those two intel
> chipsets.  These two bugs seem to be relevant:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=161242
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=160420
> 
> 

This affects all drivers that are using mmio for accessing i/o ports.
The visual effects might be different on different hardware, though.

I suggest you file a bug at freedesk.org's bugzilla (unless someone else
 already did).

- --
Thomas Winischhofer
Vienna/Austria
thomas AT winischhofer DOT net          http://www.winischhofer.net/

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