diff mbox

drm/i915: Skip shrinking of fenced objects if Gfx is suspended

Message ID 1450330153-15910-1-git-send-email-praveen.paneri@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Praveen Paneri Dec. 17, 2015, 5:29 a.m. UTC 
When the system is running low on memory, gem shrinker is invoked.
In this process objects will be unbinded from GTT.
For tiled objects, access to fence registers could be required while
unbinding them. That requires a resume of gfx device, if suspended,
in the shrinker path. This intermediate resume could cause power
leakage.
To avoid this intermediate resume of gfx device, don't consider
tiled(fenced) objects for purge in the shrinker path.

Signed-off-by: Akash Goel <akash.goel@intel.com>
Signed-off-by: Praveen Paneri <praveen.paneri@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Chris Wilson Dec. 17, 2015, 7:25 a.m. UTC | #1 
On Thu, Dec 17, 2015 at 10:59:13AM +0530, Praveen Paneri wrote:
> When the system is running low on memory, gem shrinker is invoked.
> In this process objects will be unbinded from GTT.
> For tiled objects, access to fence registers could be required while
> unbinding them. That requires a resume of gfx device, if suspended,
> in the shrinker path. This intermediate resume could cause power
> leakage.
> To avoid this intermediate resume of gfx device, don't consider
> tiled(fenced) objects for purge in the shrinker path.

Well, you can't unbind anything whilst the device is suspended (GSM is
also hardware access).

Please see the recent intel_runtime_pm_tryget() discussion.
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index f7df54a..443432a 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -129,6 +129,17 @@  i915_gem_shrink(struct drm_i915_private *dev_priv,
 			if ((flags & I915_SHRINK_ACTIVE) == 0 && obj->active)
 				continue;
 
+			/*
+			 * Skip the unbinding of objects, possessing a fence
+			 * register, if the device in the suspended state.
+			 * Otherwise device has to be resumed before an access
+			 * is made to the fence register on unbinding.
+			 */
+			if (HAS_RUNTIME_PM(dev_priv->dev) &&
+				dev_priv->pm.suspended &&
+				(obj->fence_reg != I915_FENCE_REG_NONE))
+				continue;
+
 			drm_gem_object_reference(&obj->base);
 
 			/* For the unbound phase, this should be a no-op! */