[Intel-gfx] [PATCH] drm/i915: VLV/CHV PSR Software timer mode

[R, Durgadoss]

>-----Original Message-----
>From: Vivi, Rodrigo
>Sent: Wednesday, November 19, 2014 9:08 PM
>To: intel-gfx at lists.freedesktop.org
>Cc: Vivi, Rodrigo; R, Durgadoss
>Subject: [PATCH] drm/i915: VLV/CHV PSR Software timer mode
>
>This patch introduces exit/activate functions for PSR
>on VLV+. Since on VLV+ HW cannot track frame updates and force PSR
>exit let's use fully SW tracking available.
>
>v2: Rebase over intel_psr.c;
>    Remove Single Frame update transitioning from state 3 to 5 directly;
>    Fake a software invalidation for sprites and cursor so we don't miss
>    any screen update;
>
>v3: As pointed out by Durgadoss msecs_to_jiffies used on wait_for only uses int,
>    so let's use 1 instead. Althought the 1/4 of this is needed for the
>    transition let's use 1 for simplicity;
>    Also fix comments as suggested by Durgadoss
>
>Cc: Durgadoss R <durgadoss.r at intel.com>
>Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

1 ms for transition looks fine..

Reviewed-by: Durgadoss R <durgadoss.r at intel.com>

Thanks,
Durga

>---
> drivers/gpu/drm/i915/intel_psr.c | 97 ++++++++++++++++++++++++++++++++++------
> 1 file changed, 84 insertions(+), 13 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
>index 30f341a..dd0e6e0 100644
>--- a/drivers/gpu/drm/i915/intel_psr.c
>+++ b/drivers/gpu/drm/i915/intel_psr.c
>@@ -195,6 +195,23 @@ static void vlv_psr_enable_source(struct intel_dp *intel_dp)
> 		   VLV_EDP_PSR_ENABLE);
> }
>
>+static void vlv_psr_activate(struct intel_dp *intel_dp)
>+{
>+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>+	struct drm_device *dev = dig_port->base.base.dev;
>+	struct drm_i915_private *dev_priv = dev->dev_private;
>+	struct drm_crtc *crtc = dig_port->base.base.crtc;
>+	enum pipe pipe = to_intel_crtc(crtc)->pipe;
>+
>+	/* Let's do the transition from PSR_state 1 to PSR_state 2
>+	 * that is PSR transition to active - static frame transmission.
>+	 * Then Hardware is responsible for the transition to PSR_state 3
>+	 * that is PSR active - no Remote Frame Buffer (RFB) update.
>+	 */
>+	I915_WRITE(VLV_PSRCTL(pipe), I915_READ(VLV_PSRCTL(pipe)) |
>+		   VLV_EDP_PSR_ACTIVE_ENTRY);
>+}
>+
> static void hsw_psr_enable_source(struct intel_dp *intel_dp)
> {
> 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>@@ -283,12 +300,16 @@ static void intel_psr_activate(struct intel_dp *intel_dp)
> 	WARN_ON(dev_priv->psr.active);
> 	lockdep_assert_held(&dev_priv->psr.lock);
>
>-	/* Enable/Re-enable PSR on the host
>-	 * On HSW+ after we enable PSR on source it will activate it
>-	 * as soon as it match configure idle_frame count. So
>-	 * we just actually enable it here on activation time.
>-	 */
>-	hsw_psr_enable_source(intel_dp);
>+	/* Enable/Re-enable PSR on the host */
>+	if (HAS_DDI(dev))
>+		/* On HSW+ after we enable PSR on source it will activate it
>+		 * as soon as it match configure idle_frame count. So
>+		 * we just actually enable it here on activation time.
>+		 */
>+		hsw_psr_enable_source(intel_dp);
>+	else
>+		vlv_psr_activate(intel_dp);
>+
> 	dev_priv->psr.active = true;
> }
>
>@@ -436,18 +457,27 @@ static void intel_psr_work(struct work_struct *work)
> 	struct drm_i915_private *dev_priv =
> 		container_of(work, typeof(*dev_priv), psr.work.work);
> 	struct intel_dp *intel_dp = dev_priv->psr.enabled;
>+	struct drm_crtc *crtc = dp_to_dig_port(intel_dp)->base.base.crtc;
>+	enum pipe pipe = to_intel_crtc(crtc)->pipe;
>
> 	/* We have to make sure PSR is ready for re-enable
> 	 * otherwise it keeps disabled until next full enable/disable cycle.
> 	 * PSR might take some time to get fully disabled
> 	 * and be ready for re-enable.
> 	 */
>-	if (wait_for((I915_READ(EDP_PSR_STATUS_CTL(dev_priv->dev)) &
>-		      EDP_PSR_STATUS_STATE_MASK) == 0, 50)) {
>-		DRM_ERROR("Timed out waiting for PSR Idle for re-enable\n");
>-		return;
>+	if (HAS_DDI(dev_priv->dev)) {
>+		if (wait_for((I915_READ(EDP_PSR_STATUS_CTL(dev_priv->dev)) &
>+			      EDP_PSR_STATUS_STATE_MASK) == 0, 50)) {
>+			DRM_ERROR("Timed out waiting for PSR Idle for re-enable\n");
>+			return;
>+		}
>+	} else {
>+		if (wait_for((I915_READ(VLV_PSRSTAT(pipe)) &
>+			      VLV_EDP_PSR_IN_TRANS) == 0, 1)) {
>+			DRM_ERROR("Timed out waiting for PSR Idle for re-enable\n");
>+			return;
>+		}
> 	}
>-
> 	mutex_lock(&dev_priv->psr.lock);
> 	intel_dp = dev_priv->psr.enabled;
>
>@@ -470,17 +500,47 @@ unlock:
> static void intel_psr_exit(struct drm_device *dev)
> {
> 	struct drm_i915_private *dev_priv = dev->dev_private;
>+	struct intel_dp *intel_dp = dev_priv->psr.enabled;
>+	struct drm_crtc *crtc = dp_to_dig_port(intel_dp)->base.base.crtc;
>+	enum pipe pipe = to_intel_crtc(crtc)->pipe;
>+	u32 val;
>
>-	if (dev_priv->psr.active) {
>-		u32 val = I915_READ(EDP_PSR_CTL(dev));
>+	if (!dev_priv->psr.active)
>+		return;
>+
>+	if (HAS_DDI(dev)) {
>+		val = I915_READ(EDP_PSR_CTL(dev));
>
> 		WARN_ON(!(val & EDP_PSR_ENABLE));
>
> 		I915_WRITE(EDP_PSR_CTL(dev), val & ~EDP_PSR_ENABLE);
>
> 		dev_priv->psr.active = false;
>+	} else {
>+		val = I915_READ(VLV_PSRCTL(pipe));
>+
>+		/* Here we do the transition from PSR_state 3 to PSR_state 5
>+		 * directly once PSR State 4 that is active with single frame
>+		 * update can be skipped. PSR_state 5 that is PSR exit then
>+		 * Hardware is responsible to transition back to PSR_state 1
>+		 * that is PSR inactive. Same state after
>+		 * vlv_edp_psr_enable_source.
>+		 */
>+		val &= ~VLV_EDP_PSR_ACTIVE_ENTRY;
>+		I915_WRITE(VLV_PSRCTL(pipe), val);
>+
>+		/* Send AUX wake up - Spec says after transitioning to PSR
>+		 * active we have to send AUX wake up by writing 01h in DPCD
>+		 * 600h of sink device.
>+		 * XXX: This might slow down the transition, but without this
>+		 * HW doesn't complete the transition to PSR_state 1 and we
>+		 * never get the screen updated.
>+		 */
>+		drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
>+				   DP_SET_POWER_D0);
> 	}
>
>+	dev_priv->psr.active = false;
> }
>
> /**
>@@ -558,6 +618,17 @@ void intel_psr_flush(struct drm_device *dev,
> 	    (frontbuffer_bits & INTEL_FRONTBUFFER_SPRITE(pipe)))
> 		intel_psr_exit(dev);
>
>+	/*
>+	 * On Valleyview and Cherryview we don't use hardware tracking so
>+	 * sprite plane updates or cursor moves don't result in a PSR
>+	 * invalidating. Which means we need to manually fake this in
>+	 * software for all flushes, not just when we've seen a preceding
>+	 * invalidation through frontbuffer rendering. */
>+	if (!HAS_DDI(dev) &&
>+	    ((frontbuffer_bits & INTEL_FRONTBUFFER_SPRITE(pipe)) ||
>+	     (frontbuffer_bits & INTEL_FRONTBUFFER_CURSOR(pipe))))
>+		intel_psr_exit(dev);
>+
> 	if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
> 		schedule_delayed_work(&dev_priv->psr.work,
> 				      msecs_to_jiffies(100));
>--
>1.9.3