drm/i915: Idle unused rings on gen2/3 during init/resume
gen2/3 platforms have a boatload of rings we're not using. On my 830
the BIOS/hw can leave some of those "active" after resume which will
prevent c3 entry. The ring is apparently considered active whenever
head != tail even if the ring is disabled.
Disable and clear all such unused ringbuffers on init/resume.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 60b8bd1..6c68570 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4663,11 +4663,46 @@
return true;
}
+static void init_unused_ring(struct drm_device *dev, u32 base)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ I915_WRITE(RING_CTL(base), 0);
+ I915_WRITE(RING_HEAD(base), 0);
+ I915_WRITE(RING_TAIL(base), 0);
+ I915_WRITE(RING_START(base), 0);
+}
+
+static void init_unused_rings(struct drm_device *dev)
+{
+ if (IS_I830(dev)) {
+ init_unused_ring(dev, PRB1_BASE);
+ init_unused_ring(dev, SRB0_BASE);
+ init_unused_ring(dev, SRB1_BASE);
+ init_unused_ring(dev, SRB2_BASE);
+ init_unused_ring(dev, SRB3_BASE);
+ } else if (IS_GEN2(dev)) {
+ init_unused_ring(dev, SRB0_BASE);
+ init_unused_ring(dev, SRB1_BASE);
+ } else if (IS_GEN3(dev)) {
+ init_unused_ring(dev, PRB1_BASE);
+ init_unused_ring(dev, PRB2_BASE);
+ }
+}
+
int i915_gem_init_rings(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int ret;
+ /*
+ * At least 830 can leave some of the unused rings
+ * "active" (ie. head != tail) after resume which
+ * will prevent c3 entry. Makes sure all unused rings
+ * are totally idle.
+ */
+ init_unused_rings(dev);
+
ret = intel_init_render_ring_buffer(dev);
if (ret)
return ret;