[rfc] drm/radeon/kms: pm debugging check for vbl.

This patch adds a check on avivo chips to see if we are in the VBL
region for the active crtcs when we trigger the engine change.

I appear to have glitches locally on pm transistion (not sure all
fixes are in yet) and this at least seems to be correct here,
maybe others can test on systems with no glitches.

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index f0234351fd5..6dbfdf48a5f 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -22,6 +22,7 @@
  */
 #include "drmP.h"
 #include "radeon.h"
+#include "avivod.h"
 
 #define RADEON_IDLE_LOOP_MS 100
 #define RADEON_RECLOCK_DELAY_MS 200
@@ -283,6 +284,28 @@ void radeon_pm_compute_clocks(struct radeon_device *rdev)
         mutex_unlock(&rdev->pm.mutex);
 }
 
+static bool radeon_pm_debug_check_in_vbl(struct radeon_device *rdev, bool finish)
+{
+        u32 stat_crtc1 = 0, stat_crtc2 = 0;
+        bool in_vbl = true;
+
+        if (ASIC_IS_AVIVO(rdev)) {
+                if (rdev->pm.active_crtcs & (1 << 0)) {
+                        stat_crtc1 = RREG32(D1CRTC_STATUS);
+                        if (!(stat_crtc1 & 1))
+                                in_vbl = false;
+                }
+                if (rdev->pm.active_crtcs & (1 << 1)) {
+                        stat_crtc2 = RREG32(D2CRTC_STATUS);
+                        if (!(stat_crtc2 & 1))
+                                in_vbl = false;
+                }
+        }
+        if (in_vbl == false)
+                DRM_INFO("not in vbl for pm change %08x %08x at %s\n", stat_crtc1,
+                         stat_crtc2, finish ? "exit" : "entry");
+        return in_vbl;
+}
 static void radeon_pm_set_clocks_locked(struct radeon_device *rdev)
 {
         /*radeon_fence_wait_last(rdev);*/
@@ -299,7 +322,11 @@ static void radeon_pm_set_clocks_locked(struct radeon_device *rdev)
                 DRM_ERROR("%s: PM_ACTION_NONE\n", __func__);
                 break;
         }
+
+        /* check if we are in vblank */
+        radeon_pm_debug_check_in_vbl(rdev, false);
         radeon_set_power_state(rdev);
+        radeon_pm_debug_check_in_vbl(rdev, true);
         rdev->pm.planned_action = PM_ACTION_NONE;
 }