[Intel-gfx] [PATCH] drm/i915: Fix up the forcewake timer initialization

[Chris Wilson]

On Tue, Mar 18, 2014 at 05:41:54PM -0700, Ben Widawsky wrote:
> On Tue, Mar 18, 2014 at 04:31:03PM +0100, Daniel Vetter wrote:
> > This is a regression introduced in
> > 
> > commit 0294ae7b44bba7ab0d4cef9a8736287f38bdb4fd
> > Author: Chris Wilson <chris at chris-wilson.co.uk>
> > Date:   Thu Mar 13 12:00:29 2014 +0000
> > 
> >     drm/i915: Consolidate forcewake resetting to a single function
> > 
> > The reordered setup sequence ended up calling del_timer_sync before
> > the timer was set up correctly, resulting in endless hilarity when
> > loading the driver.
> > 
> > Compared to Ben's patch (which moved around the setup_timer call to
> > sanitize_early) this moves the sanitize_early call around in the
> > driver load call. This way we avoid calling setup_timer again in the
> > resume code (where we also call sanitize_early).
> > 
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> > Cc: Ben Widawsky <benjamin.widawsky at intel.com>
> > Tested-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76242
> > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/i915_dma.c     | 2 --
> >  drivers/gpu/drm/i915/intel_uncore.c | 2 ++
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> > index e4d2b9f15ae2..9faee49f210d 100644
> > --- a/drivers/gpu/drm/i915/i915_dma.c
> > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > @@ -1608,8 +1608,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
> >  		goto put_bridge;
> >  	}
> >  
> > -	intel_uncore_early_sanitize(dev);
> > -
> >  	/* This must be called before any calls to HAS_PCH_* */
> >  	intel_detect_pch(dev);
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> > index e2e328d86aff..c3832d9270a6 100644
> > --- a/drivers/gpu/drm/i915/intel_uncore.c
> > +++ b/drivers/gpu/drm/i915/intel_uncore.c
> > @@ -736,6 +736,8 @@ void intel_uncore_init(struct drm_device *dev)
> >  	setup_timer(&dev_priv->uncore.force_wake_timer,
> >  		    gen6_force_wake_timer, (unsigned long)dev_priv);
> >  
> > +	intel_uncore_early_sanitize(dev);
> > +
> >  	if (IS_VALLEYVIEW(dev)) {
> >  		dev_priv->uncore.funcs.force_wake_get = __vlv_force_wake_get;
> >  		dev_priv->uncore.funcs.force_wake_put = __vlv_force_wake_put;
> 
> If you only want to setup_timer once, the setup_timer call should be in
> intel_uncore_init() which is the only one called only at load time. And
> of course, this is where the bug is. Otherwise, thaw calls
> uncore_early_sanitize, which will setup_timer again (which I thought was
> your complaint with my original patch).

I don't think we want to stop checking for garbage in the forcewake
registers upon resume though?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre