blob: 11f9309b019881080184cae0c95070361b633e58 [file] [log] [blame]
From 4609be6ede808afa10b534d13b88efd09aa17e63 Mon Sep 17 00:00:00 2001
From: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Fri, 9 Aug 2013 17:04:36 -0300
Subject: drm/i915: fix how we mask PMIMR when adding work to the queue
It seems we've been doing this ever since we started processing the
RPS events on a work queue, on commit "drm/i915: move gen6 rps
handling to workqueue", 4912d04193733a825216b926ffd290fada88ab07.
The problem is: when we add work to the queue, instead of just masking
the bits we queued and leaving all the others on their current state,
we mask the bits we queued and unmask all the others. This basically
means we'll be unmasking a bunch of interrupts we're not going to
process. And if you look at gen6_pm_rps_work, we unmask back only
GEN6_PM_RPS_EVENTS, which means the bits we unmasked when adding work
to the queue will remain unmasked after we process the queue.
Notice that even though we unmask those unrelated interrupts, we never
enable them on IER, so they don't fire our interrupt handler, they
just stay there on IIR waiting to be cleared when something else
triggers the interrupt handler.
So this patch does what seems to make more sense: mask only the bits
we add to the queue, without unmasking anything else, and so we'll
unmask them after we process the queue.
As a side effect we also have to remove that WARN, because it is not
only making sure we don't mask useful interrupts, it is also making
sure we do unmask useless interrupts! That piece of code should not be
responsible for knowing which bits should be unmasked, so just don't
assert anything, and trust that snb_disable_pm_irq should be doing the
right thing.
With i915.enable_pc8=1 I was getting ocasional "GEN6_PMIIR is not 0"
error messages due to the fact that we unmask those unrelated
interrupts but don't enable them.
Note: if bugs start bisecting to this patch, then it probably means
someone was relying on the fact that we unmask everything by accident,
then we should fix gen5_gt_irq_postinstall or whoever needs the
accidentally unmasked interrupts. Or maybe I was just wrong and we
need to revert this patch :)
Note: This started to be a more real issue with the addition of the
VEBOX support since now we do enable more than just the minimal set of
RPS interrupts in the IER register. Which means after the first rps
interrupt has happened we will never mask the VEBOX user interrupts
again and so will blow through cpu time needlessly when running video
workloads.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Add note that this started to matter with VEBOX much more.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 4d3b3d5fd7d42a522a6c444388826bb23264db9f)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
drivers/gpu/drm/i915/i915_irq.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index b04130e7bff2..aaad8c639a3a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -167,11 +167,6 @@ void snb_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
snb_update_pm_irq(dev_priv, mask, 0);
}
-static void snb_set_pm_irq(struct drm_i915_private *dev_priv, uint32_t val)
-{
- snb_update_pm_irq(dev_priv, 0xffffffff, ~val);
-}
-
static bool ivb_can_enable_err_int(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -963,7 +958,7 @@ static void gen6_rps_irq_handler(struct drm_i915_private *dev_priv,
spin_lock(&dev_priv->irq_lock);
dev_priv->rps.pm_iir |= pm_iir & GEN6_PM_RPS_EVENTS;
- snb_set_pm_irq(dev_priv, dev_priv->rps.pm_iir);
+ snb_disable_pm_irq(dev_priv, pm_iir & GEN6_PM_RPS_EVENTS);
spin_unlock(&dev_priv->irq_lock);
queue_work(dev_priv->wq, &dev_priv->rps.work);
@@ -1046,9 +1041,7 @@ static void hsw_pm_irq_handler(struct drm_i915_private *dev_priv,
if (pm_iir & GEN6_PM_RPS_EVENTS) {
spin_lock(&dev_priv->irq_lock);
dev_priv->rps.pm_iir |= pm_iir & GEN6_PM_RPS_EVENTS;
- snb_set_pm_irq(dev_priv, dev_priv->rps.pm_iir);
- /* never want to mask useful interrupts. */
- WARN_ON(I915_READ_NOTRACE(GEN6_PMIMR) & ~GEN6_PM_RPS_EVENTS);
+ snb_disable_pm_irq(dev_priv, pm_iir & GEN6_PM_RPS_EVENTS);
spin_unlock(&dev_priv->irq_lock);
queue_work(dev_priv->wq, &dev_priv->rps.work);
--
1.8.5.rc3