linux-4.4 bisected: kwin5 stuck on kde5 loading screen with radeon

[Vlastimil Babka]

On 01/15/2016 01:26 PM, Ville Syrjälä wrote:
> On Fri, Jan 15, 2016 at 11:34:08AM +0100, Vlastimil Babka wrote:
>>
>> I have suspected that kwin is waiting for some event, but nevertheless
>> tried bisecting the kernel between 4.3 and 4.4, which lead to:
>>
>> # first bad commit: [4dfd64862ff852df7b1198d667dda778715ee88f] drm: Use
>> vblank timestamps to guesstimate how many vblanks were missed
>>
>> I can confirm that 4.4 works if I revert the following commits:
>> 63154ff230fc9255cc507af6277cd181943c50a1 "drm/amdgpu: Fixup hw vblank
>> counter/ts for new drm_update_vblank_count() (v3)"
>>
>> d1145ad1e41b6c33758a856163198cb53bb96a50 "drm/radeon: Fixup hw vblank
>> counter/ts for new drm_update_vblank_count() (v2)"
>
> The sha1s don't seem to match what I have, so not sure which kernel tree

Hm sorry, I pasted the sha1 of the reverts by mistake.
Correct sha1 are:
5b5561b3660db734652fbd02b4b6cbe00434d96b "drm/radeon: Fixup hw vblank 
counter/ts for new drm_update_vblank_count() (v2)"
fa4270d8e0257b4b76f11baa2866f4313d29aaf5 "drm: Don't zero vblank 
timestamps from the irq handler"
235fabe09b46469adad2c9e4cb0563758155187c "drm: Add DRM_DEBUG_VBL()"
4dfd64862ff852df7b1198d667dda778715ee88f "drm: Use vblank timestamps to 
guesstimate how many vblanks were missed"
8e36f9d33c134d5c6448ad65b423a9fd94e045cf "drm/amdgpu: Fixup hw vblank 
counter/ts for new drm_update_vblank_count() (v3)"

Also, it turns out that the process actually showing the progress is
"ksplashqml", not kwin. It survives killing kwin, and restarting kwin
just makes it shown on top again, or something. If I force kill
ksplashqml instead of kwin, the desktop works including decorations
and everything. ksplashqml itself also waits in kernel in poll().

I'll try some of your suggestions, thanks!