Bug 35196

Summary: X seems to ignore Option "AccelMethod" "XAA" still using EXA
Product: xorg Reporter: Bodo Thiesen <bothie>
Component: Server/Acceleration/XAAAssignee: Xorg Project Team <xorg-team>
Status: RESOLVED NOTABUG QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
The xorg.conf used for the test
none
The Xorg.log file generated by the run none

Description Bodo Thiesen 2011-03-10 22:57:26 UTC
Created attachment 44338 [details]
The xorg.conf used for the test

In my attempts to fix my performance issues with my Radeon card, I did a test run of the X server using cmdline "valgrind --tool=callgrind /usr/bin/X.nosuid" to see, where the X server burns all those CPU cycles I see in top. The answer: In libexa.so: exa_unaccel.c. That's obvious, because if it were accellerated, I wouldn't have made the test run in the first place, what's not obvious: I explicitly asked the X server to use XAA (to test, whether that's better). It seems the X server is just ignoring that particular option alltogether.
Comment 1 Bodo Thiesen 2011-03-10 23:04:13 UTC
Created attachment 44339 [details]
The Xorg.log file generated by the run
Comment 2 Michel Dänzer 2011-03-11 02:43:42 UTC
"AccelMethod" is a driver option. The radeon driver can't support XAA with KMS.
Comment 3 Bodo Thiesen 2011-03-11 10:53:00 UTC
Oh, didn't know (found many references to the options in forums and just tried them ...). How about writing a warning message in Xorg.log like "XAA is not supported when KMS is enabled - falling back to EXA"?

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