From: Keith Packard <keithp@keithp.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
intel-gfx <intel-gfx@lists.freedesktop.org>,
Eugeni Dodonov <eugeni.dodonov@intel.com>,
stable@kernel.org
Subject: Re: [PATCH] drm/i915: paper over missed irq issues with force wake vodoo
Date: Sat, 14 Jan 2012 22:35:44 -0800 [thread overview]
Message-ID: <861ur14gn3.fsf@sumi.keithp.com> (raw)
In-Reply-To: <20120114121152.GA3583@phenom.ffwll.local>
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On Sat, 14 Jan 2012 13:12:07 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
> I think that race is air-tight with your patch to rework the reset code
> already. But better safe than sorry. And as I've said a good cleanup
> anyway.
Sounds good. I like clearer code, especially when it doesn't cost
performance. I think I'd like my version in -fixes so that we don't
change anything with -next; no reason to have two slightly different
versions out there in case one (or the other) is broken?
> One of the reasons Chris originally shot down Ben's forcewake patches
> which protected everything with a spinlock (i.e. also writes) is the
> overhead. And writes to advance the ring are actually rather common. Iirc
> Chris even wrote a patch to cut down on the overhead by caching the fifo
> count. So I think we actually want this asymmetry in locking for
> performance reasons.
Ah, that's a good reason to use different locking for each path
then. Suitable documentation, and a WARN_ON in the write path to check
for the struct_mutex should suffice to prevent mistakes in the future.
--
keith.packard@intel.com
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next prev parent reply other threads:[~2012-01-15 6:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-04 16:52 [PATCH] drm/i915: paper over missed irq issues with force wake vodoo Daniel Vetter
2012-01-04 18:15 ` Eugeni Dodonov
2012-01-04 18:40 ` Daniel Vetter
2012-01-05 2:27 ` Keith Packard
2012-01-05 11:13 ` Daniel Vetter
2012-01-05 11:23 ` Eugeni Dodonov
2012-01-05 22:11 ` [PATCH] drm/i915: rip out the HWSTAM missed irq workaround Daniel Vetter
2012-01-05 23:29 ` Ben Widawsky
2012-01-06 16:03 ` Eugeni Dodonov
2012-01-09 22:00 ` Keith Packard
2012-01-09 23:39 ` Daniel Vetter
2012-01-10 2:09 ` Keith Packard
2012-01-10 7:58 ` Daniel Vetter
2012-01-18 0:24 ` Ben Widawsky
2012-01-10 12:20 ` [PATCH] drm/i915: paper over missed irq issues with force wake vodoo Daniel Vetter
2012-01-11 0:51 ` Eric Anholt
2012-01-11 4:44 ` Keith Packard
2012-01-11 6:21 ` Ben Widawsky
2012-01-11 9:59 ` Daniel Vetter
2012-01-11 5:41 ` Kenneth Graunke
2012-01-13 16:42 ` Keith Packard
2012-01-13 23:52 ` Daniel Vetter
2012-01-13 23:55 ` Daniel Vetter
2012-01-14 0:11 ` Keith Packard
2012-01-14 0:31 ` Daniel Vetter
2012-01-14 0:50 ` Keith Packard
2012-01-14 12:12 ` Daniel Vetter
2012-01-15 6:35 ` Keith Packard [this message]
2012-01-15 15:03 ` Daniel Vetter
2012-01-16 0:06 ` Keith Packard
2012-01-05 23:29 ` Ben Widawsky
2012-01-08 13:01 ` Daniel Vetter
2012-01-09 5:09 ` Keith Packard
2012-01-06 20:56 ` Keith Packard
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