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From: Kenneth Graunke <kenneth@whitecape.org>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Use PIPE_CONTROL for flushing on gen6+.
Date: Mon, 26 Sep 2011 13:21:49 -0700	[thread overview]
Message-ID: <4E80DEDD.5090403@whitecape.org> (raw)
In-Reply-To: <d08817$1l8egs@azsmga001.ch.intel.com>

On 09/26/2011 12:16 PM, Chris Wilson wrote:
> On Mon, 26 Sep 2011 11:59:23 -0700, Kenneth Graunke <kenneth@whitecape.org> wrote:
>> From: Jesse Barnes <jbarnes@virtuousgeek.org>
> 
> From the school of "If ain't broke, don't fix it" there needs to be a real
> explanation of why this change is required here.
> 
> PIPE_CONTROL and its workarounds is a very bitter pill to swallow if
> MI_FLUSH continues to function.
> -Chris

I hear you.

The issue is that (from Eric's reading of the simulator) MI_FLUSH seems
to be equivalent to PIPE_CONTROL with some unknown set of bits
enabled...which means we likely do need workarounds.  It's just not
clear which ones.

Also, according to the BSpec, MI_FLUSH is no longer validated or
guaranteed to work on Ivybridge.  I heard they said that about
Sandybridge as well but later recanted...I don't know if they will this
time, though.

I suspect that it actually is broke, and we do need to fix it.  This
seems like a first step.

--Kenneth

  parent reply	other threads:[~2011-09-26 20:20 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-26 18:59 [PATCH] drm/i915: Use PIPE_CONTROL for flushing on gen6+ Kenneth Graunke
2011-09-26 19:16 ` Chris Wilson
2011-09-26 19:23   ` Daniel Vetter
2011-09-26 19:43     ` Chris Wilson
2011-09-26 20:15   ` Keith Packard
2011-09-26 20:21   ` Kenneth Graunke [this message]
2011-09-26 20:31 ` Daniel Vetter
2011-09-26 20:38   ` Kenneth Graunke
2011-09-26 22:25     ` Eric Anholt
2011-10-03 20:00 ` Jesse Barnes
2011-10-03 21:14   ` Keith Packard
2011-10-03 21:21     ` Jesse Barnes
2011-10-03 22:59   ` Eric Anholt
2011-10-03 23:16     ` Jesse Barnes
  -- strict thread matches above, loose matches on Subject: below --
2011-10-11 21:41 [PATCH 3/3] " Daniel Vetter
2011-10-16  8:23 ` [PATCH] " Daniel Vetter
2011-10-17  1:27   ` Ben Widawsky

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