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Groups > linux.kernel > #1313994
| From | Mario Kleiner <mario.kleiner.de@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon |
| Date | 2016-01-21 09:30 +0100 |
| Message-ID | <qTiMW-2Ez-13@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <qSfHs-7W3-11@gated-at.bofh.it> <qT7HQ-3eL-7@gated-at.bofh.it> <qTepX-7Ua-1@gated-at.bofh.it> <qTg8C-Im-39@gated-at.bofh.it> <qTh4u-1mn-17@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 01/21/2016 07:38 AM, Michel Dänzer wrote:
> On 21.01.2016 14:31, Mario Kleiner wrote:
>> On 01/21/2016 04:43 AM, Michel Dänzer wrote:
>>> On 21.01.2016 05:32, Mario Kleiner wrote:
>>>>
>>>> So the problem is that AMDs hardware frame counters reset to
>>>> zero during a modeset. The old DRM code dealt with drivers doing that by
>>>> keeping vblank irqs enabled during modesets and incrementing vblank
>>>> count by one during each vblank irq, i think that's what
>>>> drm_vblank_pre_modeset() and drm_vblank_post_modeset() were meant for.
>>>
>>> Right, looks like there's been a regression breaking this. I suspect the
>>> problem is that vblank->last isn't getting updated from
>>> drm_vblank_post_modeset. Not sure which change broke that though, or how
>>> to fix it. Ville?
>>>
>>
>> The whole logic has changed and the software counter updates are now
>> driven all the time by the hw counter.
>>
>>>
>>> BTW, I'm seeing a similar issue with drm_vblank_on/off as well, which
>>> exposed the bug fixed by 209e4dbc ("drm/vblank: Use u32 consistently for
>>> vblank counters"). I've been meaning to track that down since then; one
>>> of these days hopefully, but if anybody has any ideas offhand...
>>
>> I spent the last few hours reading through the drm and radeon code and i
>> think what should probably work is to replace the
>> drm_vblank_pre/post_modeset calls in radeon/amdgpu by drm_vblank_off/on
>> calls. These are apparently meant for drivers whose hw counters reset
>> during modeset, [...]
>
> ... just like drm_vblank_pre/post_modeset. That those were broken is a
> regression which needs to be fixed anyway. I don't think switching to
> drm_vblank_on/off is suitable for stable trees.
>
> Looking at Vlastimil's original post again, I'd say the most likely
> culprit is 4dfd6486 ("drm: Use vblank timestamps to guesstimate how many
> vblanks were missed").
>
Yes, i think reverting that one alone would likely fix it by reverting
to the old vblank update logic.
>
>> Once drm_vblank_off is called, drm_vblank_get will no-op and return an
>> error, so clients can't enable vblank irqs during the modeset - pageflip
>> ioctl and waitvblank ioctl would fail while a modeset happens -
>> hopefully userspace handles this correctly everywhere.
>
> We've fixed xf86-video-ati for this.
>
>
>> I'll hack up a patch for demonstration now.
>
> You're a bit late to that party. :)
>
> http://lists.freedesktop.org/archives/dri-devel/2015-May/083614.html
> http://lists.freedesktop.org/archives/dri-devel/2015-July/086451.html
>
>
Oops. Just sent out my little (so far untested) creations. Yes, they are
essentially the same as Daniel's patches. The only addition is to also
fix that other potential small race i describe by slightly moving the
xxx_pm_compute_clocks() calls around. And a fix for drm_vblank_get/put
imbalance in radeon_pm if vblank_on/off would be used.
-mario
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linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Vlastimil Babka <vbabka@suse.cz> - 2016-01-15 11:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-01-15 13:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Vlastimil Babka <vbabka@suse.cz> - 2016-01-15 13:50 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-16 05:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Vlastimil Babka <vbabka@suse.cz> - 2016-01-18 15:10 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Vlastimil Babka <vbabka@suse.cz> - 2016-01-20 21:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-20 21:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-21 04:50 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-21 06:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-21 07:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-21 07:50 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Daniel Vetter <daniel@ffwll.ch> - 2016-01-21 09:00 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-21 09:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Daniel Vetter <daniel@ffwll.ch> - 2016-01-21 11:10 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-22 04:10 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-01-22 16:20 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-22 19:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-23 19:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Michel Dänzer <michel@daenzer.net> - 2016-01-25 05:20 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-25 14:20 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-01-25 14:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-25 14:50 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-01-25 16:00 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-25 17:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Daniel Vetter <daniel@ffwll.ch> - 2016-01-25 20:00 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-25 20:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Daniel Vetter <daniel@ffwll.ch> - 2016-01-25 21:40 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-25 22:50 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Daniel Vetter <daniel@ffwll.ch> - 2016-01-25 23:10 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Mario Kleiner <mario.kleiner.de@gmail.com> - 2016-01-21 09:30 +0100
Re: linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon Vlastimil Babka <vbabka@suse.cz> - 2016-01-21 10:20 +0100
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