Bug 105469

I just realized that 'vrefresh' is not always valid in the requested mode.

so when I change intel_edp_compare_alt_mode() to also compare 'clock', then it is possible to select both alt_fixed_mode(40Hz) and fixed_mode(60Hz) using xrandr.

First of all. Sorry about spam.
This is mass update for our bugs. 

Sorry if you feel this annoying but with this trying to understand if bug still valid or not.
If bug investigation still in progress, please ignore this and I apologize!

If you think this is not anymore valid, please comment to the bug that can be closed.
If you haven't tested with our latest pre-upstream tree(drm-tip), can you do that also to see if issue is valid there still and if you cannot see issue there, please comment to the bug.

Closing, please re-open is issue still exists.

Yes, it still occurs:

$ uname -a
Linux 4.17.0-rc2

$ glxgears                                                                                                       
249 frames in 5.0 seconds = 49.732 FPS
241 frames in 5.0 seconds = 48.033 FPS
241 frames in 5.0 seconds = 48.034 FPS
241 frames in 5.0 seconds = 48.033 FPS
216 frames in 5.0 seconds = 43.100 FPS
241 frames in 5.0 seconds = 48.033 FPS

Main discussion is here: https://bugs.freedesktop.org/show_bug.cgi?id=103497

To sum up:

It's regression
It occurs since Linux 4.14
It's bisected to dc911f5bd8aacfcf8aabd5c26c88e04c837a938e (drm/i915/edp: Allow alternate fixed mode for eDP if available.)
It can be fixed either by adding https://bugs.freedesktop.org/attachment.cgi?id=135277 or reverting bisected commit.

It's sad that having all of the above doesn't result in any action from upstream developers for a half year.

Jani, seems like Jim's patch. Any suggestions.

(In reply to Mark Spencer from comment #4)
> Main discussion is here: https://bugs.freedesktop.org/show_bug.cgi?id=103497

If the main discussion about a regression is in the sidelines of a bug about "touchpad coasting", no wonder this has fallen between the cracks. :(

http://patchwork.freedesktop.org/patch/msgid/1523488406-21245-1-git-send-email-clinton.a.taylor@intel.com

(In reply to Jani Nikula from comment #6)
> If the main discussion about a regression is in the sidelines of a bug about
> "touchpad coasting", no wonder this has fallen between the cracks. :(

That bug is a regression too, caused by same commit and will probably fixed with same solution.

> http://patchwork.freedesktop.org/patch/msgid/1523488406-21245-1-git-send-
> email-clinton.a.taylor@intel.com

Thanks, for the link. It's great that someone is working on this.

Jani, Clint, what are next steps here?

I see this got stuck again. From last discussion in [1] there was conclusion to revert the offending commit (however it doesn't revert cleanly as so much time passed since it was introduced). Can you do this and finally put this bug to rest?

https://patchwork.freedesktop.org/patch/219719/

Please try this revert patch on top of drm-tip, and report back:

http://patchwork.freedesktop.org/patch/msgid/20180516080110.22770-1-jani.nikula@intel.com

(In reply to Jani Nikula from comment #10)
> Please try this revert patch on top of drm-tip, and report back:
> 
> http://patchwork.freedesktop.org/patch/msgid/20180516080110.22770-1-jani.
> nikula@intel.com

Applied and tested. It works as expected:

$ glxgears
308 frames in 5.0 seconds = 61.407 FPS
301 frames in 5.0 seconds = 60.019 FPS
301 frames in 5.0 seconds = 60.021 FPS

Probably it need adjustments if backported to 4.14 and 4.16. I leave to someone else testing on those. Thanks for the patch.

Fixed in drm-tip: https://cgit.freedesktop.org/drm-tip/commit/?id=d93fa1b47b8fcd149b5091f18385304f402a8e15

Thanks for the bug report, testing, and patience everyone. Please reopen if the problem persists with that commit, or reappears.