Re: lockup on boot -- drm/i915/display: Force the state compute phase once to enable PSR

["Souza, Jose" <jose.souza@intel.com>]

Hi

Yes this patch has a issue and we have a fix, I'm trying to find
someone to review it, more information: 
https://gitlab.freedesktop.org/drm/intel/issues/1151

On Tue, 2020-02-18 at 12:48 +0100, Dominik Brodowski wrote:
> On Mon, Feb 17, 2020 at 10:08:52PM +0100, Boris Brezillon wrote:
> > On Mon, 17 Feb 2020 21:09:42 +0100
> > Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > 
> > > On my old Dell XPS 13 laptop with
> > > 
> > > 00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge
> > > -OPI (rev 09)
> > > 00:02.0 VGA compatible controller: Intel Corporation HD Graphics
> > > 5500 (rev 09) (prog-if 00 [VGA controller])
> > > 
> > > booting 5.6-rc1 and -rc2 fails after the dmesg line
> > > 
> > > 	fb0: switching to inteldrmfb from simple
> > > 
> > > while the next lines should be something like (v5.5):
> > > 
> > > 	Console: switching to colour dummy device 80x25
> > > 	i915 0000:00:02.0: vgaarb: deactivate vga console
> > > 	[drm] ACPI BIOS requests an excessive sleep of 25000 ms, using
> > > 1500 ms instead
> > > 	[drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> > > 	[drm] Driver supports precise vblank timestamp query.
> > > 	i915 0000:00:02.0: vgaarb: changed VGA decodes:
> > > olddecodes=io+mem,decodes=io+mem:owns=io+mem
> > > 
> > > A git bisect lead to
> > > 
> > > 	commit b86d895524ab ("drm/bridge: Add an ->atomic_check()
> > > hook")
> > 
> > This commit has been reverted: you should ignore any failures
> > between
> > b86d895524ab ("drm/bridge: Add an ->atomic_check() hook") and
> > 099126352303 ("Revert "drm/bridge: Add a drm_bridge_state object").
> 
> A new bisect now points to
> 
> 	60c6a14b489b ("drm/i915/display: Force the state compute phase
> 	once to enable PSR").
> 
> Please note that bisecting this is quite a hassle, in particular due
> to
> various reverts in between and back-merges (such as ec027b33c8bb,
> which has
> two parents in "bad" state). As 60c6a14b489b does not revert cleanly,
> I
> can't test a revert on top of 5.6-rc2.
> 
> Thanks,
> 	Dominik