[Intel-gfx] [PATCH 02/11] drm/i915: Fix oopses in the overlay code due to i915_gem_active stuff

[Ville Syrjälä]

On Wed, Dec 07, 2016 at 05:44:15PM +0000, Chris Wilson wrote:
> On Wed, Dec 07, 2016 at 07:28:04PM +0200, ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > The i915_gem_active stuff doesn't like a NULL ->retire hook, but
> > the overlay code can set it to NULL. That obviously ends up oopsing.
> > Fix it by setting the ->retire hook using init_request_active()
> > so that it'll do the NULL->i915_gem_retire_noop conversion for us.
> > 
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Fixes: 0d9bdd886f29 ("drm/i915: Convert intel_overlay to request tracking")
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_overlay.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
> > index 1cc963814224..786389dd5175 100644
> > --- a/drivers/gpu/drm/i915/intel_overlay.c
> > +++ b/drivers/gpu/drm/i915/intel_overlay.c
> > @@ -216,7 +216,7 @@ static void intel_overlay_submit_request(struct intel_overlay *overlay,
> >  {
> >  	GEM_BUG_ON(i915_gem_active_peek(&overlay->last_flip,
> >  					&overlay->i915->drm.struct_mutex));
> > -	overlay->last_flip.retire = retire;
> > +	init_request_active(&overlay->last_flip, retire);
> 
> Hmm, init, not reinit.

Does it matter? The list head is the other thing in there I guess, but
at this point it shouldn't be on any list anymore AFAICS.

> The alternative is to use i915_gem_retire_noop
> instead of NULL. (And sorry, it did used to allow NULL.)
> 
> overlay->last_flip.retire = retire ?= i915_gem_retire_noop;
> 
> Or i915_gem_active_set_retire_fn(&overlay->last_flip, retire);
> That's seems like it should make everyone a bit happier.
> -Chris
> 
> -- 
> Chris Wilson, Intel Open Source Technology Centre

-- 
Ville Syrjälä
Intel OTC