From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= <ville.syrjala@linux.intel.com>
Subject: Re: [PATCH 2/2] drm/i915: Warn if ring tail is not
 qword aligned
Date: Mon, 26 Nov 2012 19:40:16 +0200
Message-ID: <20121126174016.GB20128@intel.com>
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To: Chris Wilson <chris@chris-wilson.co.uk>
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On Mon, Nov 26, 2012 at 04:25:47PM +0000, Chris Wilson wrote:
> On Mon, 26 Nov 2012 14:48:19 +0200, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrj=E4l=E4 <ville.syrjala@linux.intel.com>
> > =

> > Ringbuffer tail pointer must be qword aligned. Warn if someone
> > makes a mistake and forgets to pad the ring when the commands
> > inserted into the ring don't align to qword naturally.
> =

> The assertion should be that we wrote precisely the number of dwords we
> declared in intel_ring_begin(). Which is one of the important factors to
> check whenever reviewing such code. This assertion (which should be a
> BUG_ON) is no substitute for such review.

Yeah. I was considering adding some reserved_space field to the ring,
populate it in ring_begin(), and and make sure it was correctly
consumed at ring_advance(). If you think that sounds good, I can cook
up a patch for it.

-- =

Ville Syrj=E4l=E4
Intel OTC