[Intel-gfx] screen freeze with 5.2-rc6 Dell XPS-13 skylake i915

[James Bottomley]

On Thu, 2019-07-11 at 20:25 +0000, Souza, Jose wrote:
> On Thu, 2019-07-11 at 13:11 -0700, James Bottomley wrote:
> > On Thu, 2019-07-11 at 10:29 +0100, Chris Wilson wrote:
> > > Quoting James Bottomley (2019-06-29 19:56:52)
> > > > The symptoms are really weird: the screen image is locked in
> > > > place.  The machine is still functional and if I log in over
> > > > the network can do anything I like, including killing the X
> > > > server and the display will never alter.  It also seems that
> > > > the system is accepting keyboard input because when it freezes
> > > > I can cat information to a file (if the mouse was over an
> > > > xterm) and verify over the network the file contents. Nothing
> > > > unusual appears in dmesg when the lockup happens.
> > > > 
> > > > The last kernel I booted successfully on the system was 5.0, so
> > > > I'll try compiling 5.1 to narrow down the changes.
> > > 
> > > It's likely this is panel self-refresh going haywire.
> > > 
> > > commit 8f6e87d6d561f10cfa48a687345512419839b6d8
> > > Author: José Roberto de Souza <jose.souza at intel.com>
> > > Date:   Thu Mar 7 16:00:50 2019 -0800
> > > 
> > >     drm/i915: Enable PSR2 by default
> > > 
> > >     The support for PSR2 was polished, IGT tests for PSR2 was
> > > added and
> > >     it was tested performing regular user workloads like
> > > browsing,
> > >     editing documents and compiling Linux, so it is time to
> > > enable it by
> > >     default and enjoy even more power-savings.
> > > 
> > > Temporary workaround would be to set i915.enable_psr=0
> > 
> > It looks plausible.  I have to say I was just about to mark a
> > bisect containing this as good, but that probably reflects my
> > difficulty
> > reproducing the issue.
> 
> Take at look of what PSR version is supported by your panel, it
> likely that a notebook shipped with Skylake will have panel that
> supports only PSR1 so that patch has no effect on your machine.
> 
> sudo more /sys/kernel/debug/dri/0/i915_edp_psr_status
> Sink support: yes [0x01]

It says

Sink support: yes [0x01]
PSR mode: PSR1 enabled
Source PSR ctl: enabled [0x81f00726]
Source PSR status: IDLE [0x04010212]
Busy frontbuffer bits: 0x00000000


I've also updated to the released 5.2 kernel and am running with the
debug parameters you requested ... but so far no reproduction.

James