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[1/4,v3] drm/i915: Early exit from rps worker if GPU is idle

Message ID 1463496038-8242-1-git-send-email-michal.winiarski@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

MichaƂ Winiarski May 17, 2016, 2:40 p.m. UTC
This allows us to avoid the situation where worker is increasing the GPU
frequency after we've switched to idle.

v2: Do not access ->mm.busy under ->irq_lock
v3: Really do not access ->mm.busy under ->irq_lock

References: https://bugs.freedesktop.org/show_bug.cgi?id=89728
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Micha? Winiarski <michal.winiarski@intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Chris Wilson May 17, 2016, 3:05 p.m. UTC | #1
On Tue, May 17, 2016 at 04:40:38PM +0200, Micha? Winiarski wrote:
> This allows us to avoid the situation where worker is increasing the GPU
> frequency after we've switched to idle.
> 
> v2: Do not access ->mm.busy under ->irq_lock
> v3: Really do not access ->mm.busy under ->irq_lock

This is backwards. The rps worker should not be running when the device
is idle. The code tries to do that currently but fails, so I think this
as papering over the bug.

Fixing this means we can remove the DISABLE_RPM_WAKEREF_ASSERTS. The
patch I've previously sent does
https://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=tasklet&id=1c0ace26e80188e53a18977e5ef90ab8a801027c
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index f0d9414..03af766 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1089,6 +1089,9 @@  static void gen6_pm_rps_work(struct work_struct *work)
 	int new_delay, adj, min, max;
 	u32 pm_iir;
 
+	if (!dev_priv->mm.busy)
+		return;
+
 	spin_lock_irq(&dev_priv->irq_lock);
 	/* Speed up work cancelation during disabling rps interrupts. */
 	if (!dev_priv->rps.interrupts_enabled) {