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From: Ben Widawsky <ben@bwidawsk.net>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 1/3] drm/i915: close PM interrupt masking races in the irq handler
Date: Sun, 4 Sep 2011 10:09:10 -0700
Message-ID: <20110904100910.56ffb1f7@bwidawsk.net> (raw)
In-Reply-To: <1315150502-12537-2-git-send-email-daniel.vetter@ffwll.ch>

On Sun,  4 Sep 2011 17:35:00 +0200
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:

> Quoting Chris Wilson's more concise description:
> 
> "Ah I think I see the problem. As you point out we only mask the
> current interrupt received, so that if we have a task pending (and so
> IMR != 0) we actually unmask the pending interrupt and so could
> receive it again before the tasklet is finally kicked off by the
> grumpy scheduler."
> 
> So we need the hw to issue PM interrupts A, B, A while the scheduler
> is hating us and refuses to run the rps work item. On receiving PM
> interrupt A we hit the
> WARN because
> 
> dev_priv->pm_iir == PM_A | PM_B
> 
> Also add a posting read as suggested by Chris to ensure proper
> ordering of the writes to PMIMR and PMIIR. Just in case somebody
> weakens write ordering.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

  reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-04  3:24 [PATCH] drm/i915: Fix rps irq warning Ben Widawsky
2011-09-04  9:03 ` Chris Wilson
2011-09-04 15:49   ` Ben Widawsky
2011-09-04 15:34     ` [PATCH 0/3] slaughter rps races some more Daniel Vetter
2011-09-04 15:35       ` [PATCH 1/3] drm/i915: close PM interrupt masking races in the irq handler Daniel Vetter
2011-09-04 17:09         ` Ben Widawsky [this message]
2011-09-04 15:35       ` [PATCH 2/3] drm/i915: close PM interrupt masking races in the rps work func Daniel Vetter
2011-09-04 17:08         ` Ben Widawsky
2011-09-04 19:26           ` Daniel Vetter
2011-09-04 19:56             ` Ben Widawsky
2011-09-04 20:10               ` Daniel Vetter
2011-09-04 21:38                 ` Ben Widawsky
2011-09-05  6:38                   ` Daniel Vetter
2011-09-05  6:51                     ` Ben Widawsky
2011-09-05 12:15                       ` Chris Wilson
2011-09-04 15:35       ` [PATCH 3/3] drm/i915: close rps work vs. rps disable races Daniel Vetter
2011-09-04 17:23         ` Ben Widawsky
2011-09-04 19:17           ` Daniel Vetter
2011-09-04 19:50             ` Ben Widawsky
2011-09-04 19:57               ` Daniel Vetter
2011-09-05  8:15                 ` [PATCH] drm/i915: properly cancel rps_work on module unload Daniel Vetter
2011-09-05 17:27                   ` Ben Widawsky
2011-09-08 12:00 [PATCH 1/3] drm/i915: close PM interrupt masking races in the irq handler Daniel Vetter
2011-09-08 20:43 ` Chris Wilson
2011-09-23 16:08 ` Daniel Vetter
2012-04-15  9:06 ` Chris Wilson

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