From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>,
daniele.ceraolospurio@intel.com, intel-gfx@lists.freedesktop.org,
John Harrison <John.C.Harrison@Intel.com>
Subject: Re: [PATCH v3] drm/i915: check that rpm ref is held when accessing ringbuf in stolen mem
Date: Wed, 10 Feb 2016 08:56:39 +0100 [thread overview]
Message-ID: <20160210075639.GL11240@phenom.ffwll.local> (raw)
In-Reply-To: <20160127164437.GG8281@nuc-i3427.alporthouse.com>
On Wed, Jan 27, 2016 at 04:44:37PM +0000, Chris Wilson wrote:
> On Wed, Jan 27, 2016 at 03:43:49PM +0000, daniele.ceraolospurio@intel.com wrote:
> > From: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> >
> > While running some tests on the scheduler patches with rpm enabled I
> > came across a corruption in the ringbuffer, which was root-caused to
> > the GPU being suspended while commands were being emitted to the
> > ringbuffer. The access to memory was failing because the GPU needs to
> > be awake when accessing stolen memory (where my ringbuffer was located).
> > Since we have this constraint it looks like a sensible idea to check
> > that we hold a refcount when we access the rungbuffer.
> >
> > v2: move the check from ring_begin to ringbuffer iomap time (Chris)
> > v3: update comment (Chris)
> >
> > Cc: John Harrison <John.C.Harrison@Intel.com>
> > Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>
> That explains itself nicely, thanks.
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Queued for -next, thanks for the patch.
> It also rings alarms bells for intel_fbdev.c
Oops, indeed. Might explain why we sometimes just die? And fundamentally
it's unfixable (without a shadow fb) since we can't intercept mmaps on
fbdev. But maybe we need to do that (and use the damage tracking that's
already there in 3 copies in various drivers for uploading).
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2016-02-10 7:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-27 15:43 [PATCH v3] drm/i915: check that rpm ref is held when accessing ringbuf in stolen mem daniele.ceraolospurio
2016-01-27 16:39 ` Ville Syrjälä
2016-01-28 10:55 ` Daniele Ceraolo Spurio
2016-01-28 11:45 ` Chris Wilson
2016-01-28 12:09 ` Ville Syrjälä
2016-01-28 12:30 ` Chris Wilson
2016-01-27 16:44 ` Chris Wilson
2016-02-10 7:56 ` Daniel Vetter [this message]
2016-01-28 9:58 ` ✓ Fi.CI.BAT: success for drm/i915: check that rpm ref is held when accessing ringbuf in stolen mem (rev2) Patchwork
2016-01-28 16:23 ` Patchwork
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