From: Chris Wilson <chris@chris-wilson.co.uk>
To: Eric Anholt <eric@anholt.net>,
ville.syrjala@linux.intel.com, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 1/2] drm/i915: Kill i915_gem_execbuffer_wait_for_flips()
Date: Thu, 01 Nov 2012 08:58:16 +0000 [thread overview]
Message-ID: <b94cdc$762p3t@fmsmga001.fm.intel.com> (raw)
In-Reply-To: <87d2zy89aw.fsf@eliezer.anholt.net>
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On Wed, 31 Oct 2012 17:18:47 -0700, Eric Anholt <eric@anholt.net> wrote:
> ville.syrjala@linux.intel.com writes:
>
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > As per Chris Wilson's suggestion make
> > i915_gem_execbuffer_wait_for_flips() go away.
> >
> > This was used to stall the GPU ring while there are pending
> > page flips involving the relevant BO. Ie. while the BO is still
> > being scanned out by the display controller.
> >
> > The recommended alternative is to use the page flip events to
> > wait for the page flips to fully complete before reusing the BO
> > of the old front buffer. Or use more buffers.
>
> So, after this change, if userland submits an execbuf between having
> requested a pageflip and the vblank that the flip shows up on, does that
> exec block?
The code itself is dysfunctional and would cause a GPU hang on snb/ivb.
Why should the kernel be imposing a policy upon userspace where none is
required?
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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next prev parent reply other threads:[~2012-11-01 8:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-31 17:38 [PATCH 0/2] drm/i915: Page flip stuff ville.syrjala
2012-10-31 17:38 ` [PATCH 1/2] drm/i915: Kill i915_gem_execbuffer_wait_for_flips() ville.syrjala
2012-10-31 19:17 ` Ville Syrjälä
2012-11-01 0:18 ` Eric Anholt
2012-11-01 8:58 ` Chris Wilson [this message]
2012-10-31 17:38 ` [PATCH 2/2] drm/i915: Wait for pending flips in intel_pipe_set_base() ville.syrjala
2012-10-31 17:43 ` Chris Wilson
2012-10-31 18:17 ` Ville Syrjälä
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