[Intel-gfx] [PATCH 01/16] drm/i915: vlv: fix gunit HW state corruption during S4 suspend

[Imre Deak]

The point of doing these in thaw_early is to work around an ordering
issue wrt. to the hda driver, see the comment in i915_resume_early(). I
don't see a problem of having them in thaw_early; if you meant that they
lack the corresponding cleanup calls in freeze_late, it's just because
they don't have any.

On Mon, 2014-09-15 at 22:56 +0530, Sagar Arun Kamble wrote:
> From DPM documentation, thaw_early should undo actions by freeze_late.
> Can we move following snippet from thaw_early to thaw to comply with
> this?
> 
> 	intel_uncore_early_sanitize(dev, true);
>         intel_uncore_sanitize(dev);
>         intel_power_domains_init_hw(dev_priv);
> 
> On Wed, 2014-09-10 at 18:16 +0300, Imre Deak wrote:
> > During S4 freeze we don't call intel_suspend_complete(), which would
> > save the gunit HW state, but during S4 thaw/restore events we call
> > intel_resume_prepare() which restores it, thus ending up in a corrupted
> > HW state.
> > 
> > Fix this by calling intel_suspend_complete() from the corresponding
> > freeze_late event handler.
> > 
> > The issue was introduced in
> > commit 016970beb05da6285c2f3ed2bee1c676cb75972e
> > Author: Sagar Kamble <sagar.a.kamble at intel.com>
> > Date:   Wed Aug 13 23:07:06 2014 +0530
> > 
> > CC: Sagar Kamble <sagar.a.kamble at intel.com>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index b8bd008..2365875 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -987,6 +987,15 @@ static int i915_pm_freeze(struct device *dev)
> >  	return i915_drm_freeze(drm_dev);
> >  }
> >  
> > +static int i915_pm_freeze_late(struct device *dev)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> > +	struct drm_device *drm_dev = pci_get_drvdata(pdev);
> > +	struct drm_i915_private *dev_priv = drm_dev->dev_private;
> > +
> > +	return intel_suspend_complete(dev_priv);
> > +}
> > +
> >  static int i915_pm_thaw_early(struct device *dev)
> >  {
> >  	struct pci_dev *pdev = to_pci_dev(dev);
> > @@ -1571,6 +1580,7 @@ static const struct dev_pm_ops i915_pm_ops = {
> >  	.resume_early = i915_pm_resume_early,
> >  	.resume = i915_pm_resume,
> >  	.freeze = i915_pm_freeze,
> > +	.freeze_late = i915_pm_freeze_late,
> >  	.thaw_early = i915_pm_thaw_early,
> >  	.thaw = i915_pm_thaw,
> >  	.poweroff = i915_pm_poweroff,
> 
>