[PATCH] drm/i915/psr: Add PSR pause/resume reference count

[Jouni Högander]

We have now seen this:

<4> [2120.434153] i915 0000:00:02.0: [drm] drm_WARN_ON(psr->paused)
<4> [2120.434196] WARNING: CPU: 3 PID: 4430 at 
drivers/gpu/drm/i915/display/intel_psr.c:2227 intel_psr_pause+0x16e/0x180 [i915]

Comment for drm_WARN_ON(display->drm, psr->paused) in intel_psr_pause says:

"If we ever hit this, we will need to add refcount to pause/resume"

This patch is implementing PSR pause/resume refcount.

Signed-off-by: Jouni Högander <jouni.hogan...@intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  2 +-
 drivers/gpu/drm/i915/display/intel_psr.c      | 26 +++++++++----------
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
b/drivers/gpu/drm/i915/display/intel_display_types.h
index 99a6fd2900b9c..65c808bba1c6c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1620,7 +1620,7 @@ struct intel_psr {
        bool sink_support;
        bool source_support;
        bool enabled;
-       bool paused;
+       int pause_counter;
        enum pipe pipe;
        enum transcoder transcoder;
        bool active;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c 
b/drivers/gpu/drm/i915/display/intel_psr.c
index 4e938bad808cc..4d4ecf7555b66 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -2024,7 +2024,7 @@ static void intel_psr_enable_locked(struct intel_dp 
*intel_dp,
 
        intel_psr_enable_source(intel_dp, crtc_state);
        intel_dp->psr.enabled = true;
-       intel_dp->psr.paused = false;
+       intel_dp->psr.pause_counter = 0;
 
        /*
         * Link_ok is sticky and set here on PSR enable. We can assume link
@@ -2210,7 +2210,6 @@ void intel_psr_disable(struct intel_dp *intel_dp,
  */
 void intel_psr_pause(struct intel_dp *intel_dp)
 {
-       struct intel_display *display = to_intel_display(intel_dp);
        struct intel_psr *psr = &intel_dp->psr;
 
        if (!CAN_PSR(intel_dp) && !CAN_PANEL_REPLAY(intel_dp))
@@ -2223,12 +2222,10 @@ void intel_psr_pause(struct intel_dp *intel_dp)
                return;
        }
 
-       /* If we ever hit this, we will need to add refcount to pause/resume */
-       drm_WARN_ON(display->drm, psr->paused);
-
-       intel_psr_exit(intel_dp);
-       intel_psr_wait_exit_locked(intel_dp);
-       psr->paused = true;
+       if (intel_dp->psr.pause_counter++ == 0) {
+               intel_psr_exit(intel_dp);
+               intel_psr_wait_exit_locked(intel_dp);
+       }
 
        mutex_unlock(&psr->lock);
 
@@ -2251,13 +2248,14 @@ void intel_psr_resume(struct intel_dp *intel_dp)
 
        mutex_lock(&psr->lock);
 
-       if (!psr->paused)
-               goto unlock;
+       if (!psr->enabled) {
+               mutex_unlock(&psr->lock);
+               return;
+       }
 
-       psr->paused = false;
-       intel_psr_activate(intel_dp);
+       if (--intel_dp->psr.pause_counter == 0)
+               intel_psr_activate(intel_dp);
 
-unlock:
        mutex_unlock(&psr->lock);
 }
 
@@ -3322,7 +3320,7 @@ void intel_psr_flush(struct intel_display *display,
                 * we have to ensure that the PSR is not activated until
                 * intel_psr_resume() is called.
                 */
-               if (intel_dp->psr.paused)
+               if (intel_dp->psr.pause_counter)
                        goto unlock;
 
                if (origin == ORIGIN_FLIP ||
-- 
2.43.0