Re: [PATCH] Revert "drm/i915: Allocate context objects from stolen"

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] Revert "drm/i915: Allocate context objects from	stolen"
Date: Tue, 30 Jun 2015 13:07:43 +0300	[thread overview]
Message-ID: <20150630100743.GM5176@intel.com> (raw)
In-Reply-To: <20150630094415.GA1381@nuc-i3427.alporthouse.com>

On Tue, Jun 30, 2015 at 10:44:15AM +0100, Chris Wilson wrote:
> On Tue, Jun 30, 2015 at 11:31:54AM +0300, Jani Nikula wrote:
> > On Mon, 29 Jun 2015, ville.syrjala@linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > >
> > > Stolen gets trashed during hibernation, so storing contexts there
> > > is not a very good idea. On my IVB machines this leads to a totally
> > > dead GPU on resume. A reboot is required to resurrect it. So let's
> > > not store contexts where they will get trampled.
> > >
> > > This reverts commit 149c86e74fe44dcbac5e9f8d145c5fbc5dc21261.
> > 
> > Looks like a *partial* revert of
> > 
> > commit 149c86e74fe44dcbac5e9f8d145c5fbc5dc21261
> > Author: Chris Wilson <chris@chris-wilson.co.uk>
> > Date:   Tue Apr 7 16:21:11 2015 +0100
> > 
> >     drm/i915: Allocate context objects from stolen
> > 
> > and the not reverted hunk has been touched since in 
> > 
> > commit 3126a660f352b3fe48125a8a0b4fdbf85935d8bf
> > Author: Dan Carpenter <dan.carpenter@oracle.com>
> > Date:   Thu Apr 30 17:30:50 2015 +0300
> > 
> >     drm/i915: checking IS_ERR() instead of NULL
> > 
> > The commit message should say it's a partial revert and not claim
> > otherwise, and document why not everything was reverted.
> > 
> > The above commits are in Linus' tree.
> 
> The fixes I have planned to migrate context objects on hibernation are
> not of the simple variety! Revert now, fix later.
> 
> Given Ville's discovery, it also makes
> 
> commit 8040513870399f1cb032cb8bc805df5042fedcdf
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Thu Nov 15 11:32:29 2012 +0000
> 
>     drm/i915: Allocate overlay registers from stolen memory
> 
> suspect.

Hmm. It does look like it might not reinitialize the entire register
block on suspend.

-- 
Ville Syrjälä
Intel OTC
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