Re: [PATCH] drm/i915: Add missing ring_mask to Pineview

From: Daniel Vetter <daniel@ffwll.ch>
To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	intel-gfx@lists.freedesktop.org, Ben Widawsky <ben@bwidawsk.net>
Subject: Re: [PATCH] drm/i915: Add missing ring_mask to Pineview
Date: Fri, 29 Jul 2016 10:57:49 +0200	[thread overview]
Message-ID: <20160729085749.GW6232@phenom.ffwll.local> (raw)
In-Reply-To: <1469781744.4094.59.camel@linux.intel.com>

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@chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Ben Widawsky <ben@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@linux.intel.com>

dim says this also needs a

Cc: drm-intel-fixes@lists.freedesktop.org

> 
> >  	WARN_ON(INTEL_INFO(dev_priv)->ring_mask &
> >  		GENMASK(sizeof(mask) * BITS_PER_BYTE - 1, I915_NUM_ENGINES));
> >  
> -- 
> Joonas Lahtinen
> Open Source Technology Center
> Intel Corporation

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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