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From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: intel-gfx@lists.freedesktop.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, Ben Widawsky <ben@bwidawsk.net>
Subject: [PATCH 3/3] drm/i915: close rps work vs. rps disable races
Date: Sun,  4 Sep 2011 17:35:02 +0200
Message-ID: <1315150502-12537-4-git-send-email-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <1315150502-12537-1-git-send-email-daniel.vetter@ffwll.ch>

The rps disabling code wasn't properly cancelling outstanding work
items. Also add a comment that explains why we're not racing with
the work item, that could again unmask interrupts.

This also fixes a bug on module unload because nothing was properly
syncing up with that work item, possibly leading to it being run after
freeing dev_priv or removing the module code.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/intel_display.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 56a8554..ccd4600 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7483,10 +7483,16 @@ void gen6_disable_rps(struct drm_device *dev)
 
 	I915_WRITE(GEN6_RPNSWREQ, 1 << 31);
 	I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
-	I915_WRITE(GEN6_PMIER, 0);
+	/* Complete PM interrupt masking here doesn't race with the rps work
+	 * item again unmasking PM interrupts because that is using PMIMR
+	 * (logically sitting atop of PMINTRMSK) to mask interrupts. */
+	cancel_work_sync(&dev_priv->rps_work);
 
+	/* Clear PMIMR and dev_priv->pm_iir in case outstanding work gets
+	 * cancelled before having run. */
 	spin_lock_irq(&dev_priv->rps_lock);
 	dev_priv->pm_iir = 0;
+	I915_WRITE(GEN6_PMIER, 0);
 	spin_unlock_irq(&dev_priv->rps_lock);
 
 	I915_WRITE(GEN6_PMIIR, I915_READ(GEN6_PMIIR));
-- 
1.7.6

  parent reply index

Thread overview: 22+ 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
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       ` Daniel Vetter [this message]
2011-09-04 17:23         ` [PATCH 3/3] drm/i915: close rps work vs. rps disable races 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

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