Red Hat Bugzilla – Bug 826279
grub2 selects wrong video refresh rate for ATI Radeon 5500 (REDWOOD) card
Last modified: 2012-11-13 12:15:29 EST
Created attachment 587544 [details]
probed EDID info for monitor from Xorg.0.log
Description of problem:
GRUB2_GFXMODE=auto selects an invalid mode for the ATU Radeon 5500 and monitor combo. Setting to 1024x768 works.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
monitor is overdriven because the "wrong" sync frequency is selected.
01:00.0 VGA compatible controller: ATI Technologies Inc Redwood PRO [Radeon HD 5500 Series]
extract of Xorg.0.log attached showing EDID info from monitor:
(Hannspree 1600x900 LCD flat panel)
Do explicitly setting 1600x900 work?
swttung 1600x900 fails
1280x1024 works (from Xorg.0.log probed modes)
anything higher seems to overdrive the monitor. Still testing combinations.
Anything greater than 1280x<N> makes grub2 overdrive the monitor.
Attaching Xorg.0.log and non-quiet dmesg output from kernel-3.3.7
Created attachment 587554 [details]
Xorg.0.log of running system
Created attachment 587555 [details]
non-quiet dmesg output from kernel-3.3.7 (x86_64)
The kernel vesafb do for some reason use 1280x960x32.
What resolution do X use? It seems like it uses 1600x900 - does that work?
Yes, the X server uses the 1600x900 mode (as does a gentoo kernel that has 1600x900 buikt into the kernel)
So the resolution is ok - it is just 'something else' that is wrong.
Can you show a photo of the bad graphic?
The monitor displays a "signal out of range" message
grub2 is selecting too high a refresh rate compared to the KMS and Xorg server.
What is the output of
on the grub command line?
The videoinfo dump gives lots of "modeline"-like entries for the VBE type adapter.
It does not detect a "VGA". Cirrus or anything other than the VBE adapter.
I not that many of the modes it lists are inappropriate for the particular monitor being used.
BTW is there a way to capture the output into a file or something? I have no cameras to capture the output.
Created attachment 588659 [details]
Could you try this patch?
The patch is included in the unofficial beta6 scratch build on http://koji.fedoraproject.org/koji/taskinfo?taskID=4121699
Install grub2 and grub2-tools rpms,
grub2-mkconfig -o /boot/grub2/grub.cfg
Downloaded, will test
It works with gfxmode=auto
(In reply to comment #17)
> It works with gfxmode=auto
Cool. This is the (implicit) default, so this grub version should work out of the box on existing installations without any /etc/default/grub changes. Do you agree?
Yes, it seems to be working for me.
I look forward to seeing it in updates-testing.
now irrelevant, was fixed by the actions shown above