[Intel-gfx] [PATCH] drm/i915: Add missing ring_mask to Pineview

[Ben Widawsky]

On Fri, Jul 29, 2016 at 12:10:30PM +0100, Chris Wilson wrote:
> On Fri, Jul 29, 2016 at 10:57:49AM +0200, Daniel Vetter wrote:
> > On Fri, Jul 29, 2016 at 11:42:24AM +0300, Joonas Lahtinen wrote:
> > > On pe, 2016-07-29 at 00:45 +0100, Chris Wilson wrote:
> > > > It appears that we never told Pineview it has a RENDER_RING. This was
> > > > all fine until we started using the ring_mask for determining all the
> > > > available rings to initialise for legacy ringbuffer submission in commit
> > > > 88d2ba2e95c8 ("drm/i915: Unify engine init loop"). Though really it is a
> > > > latent bug since the ring_mask inception in commit 73ae478cdf6a
> > > > ("drm/i915: Replace has_bsd/blt/vebox with a mask").
> > > > 
> > > > To prevent similar mishaps in future, add a WARN_ON() if we find
> > > > ourselves with a device without any rings.
> > > > 
> > > > Fixes: 73ae478cdf6a ("drm/i915: Replace has_bsd/blt/vebox with a mask")
> > > > Fixes: 88d2ba2e95c8 ("drm/i915: Unify engine init loop")
> > > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > > > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > > Cc: Ben Widawsky <ben at bwidawsk.net>
> > > > ---
> > > >  drivers/gpu/drm/i915/i915_pci.c        | 1 +
> > > >  drivers/gpu/drm/i915/intel_engine_cs.c | 1 +
> > > >  2 files changed, 2 insertions(+)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> > > > index 949c01686a66..2587b1bd41f4 100644
> > > > --- a/drivers/gpu/drm/i915/i915_pci.c
> > > > +++ b/drivers/gpu/drm/i915/i915_pci.c
> > > > @@ -173,6 +173,7 @@ static const struct intel_device_info intel_pineview_info = {
> > > >  	.gen = 3, .is_g33 = 1, .is_pineview = 1, .is_mobile = 1, .num_pipes = 2,
> > > >  	.need_gfx_hws = 1, .has_hotplug = 1,
> > > >  	.has_overlay = 1,
> > > > +	.ring_mask = RENDER_RING,
> > > >  	GEN_DEFAULT_PIPEOFFSETS,
> > > >  	CURSOR_OFFSETS,
> > > >  };
> > > > diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> > > > index 31d43dfa7469..e6422aac2919 100644
> > > > --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> > > > +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> > > > @@ -117,6 +117,7 @@ int intel_engines_init(struct drm_device *dev)
> > > >  	unsigned int i;
> > > >  	int ret;
> > > >  
> > > > +	WARN_ON(INTEL_INFO(dev_priv)->ring_mask == 0);
> > > 
> > > Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > 
> > dim says this also needs a
> > 
> > Cc: drm-intel-fixes at lists.freedesktop.org
> 
> dim says nothing of the sort for me. The bug is only relevant from
> 88d2ba2e95c8
> -Chris
> 

I was about to say I can't imagine that a bug like this would have existed for
that long without anybody yelling about it.

-- 
Ben Widawsky, Intel Open Source Technology Center