drm: add debug print to update_vblank_count

Since we are logging all vblank counter updates 30 lines below,
it is also good to have some details whether and how vblank count
difference is calculated.

Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613121802.2193-1-oleg.vasilev@intel.com

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 0d704bddb1a672f2679d6706577b5480ce41c856..603ab105125d4112aada8f72bb79a9b766f38c38 100644 (file)
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -241,12 +241,16 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
                 * on the difference in the timestamps and the
                 * frame/field duration.
                 */
+
+               DRM_DEBUG_VBL("crtc %u: Calculating number of vblanks."
+                             " diff_ns = %lld, framedur_ns = %d)\n",
+                             pipe, (long long) diff_ns, framedur_ns);
+
                diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
 
                if (diff == 0 && in_vblank_irq)
-                       DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored."
-                                     " diff_ns = %lld, framedur_ns = %d)\n",
-                                     pipe, (long long) diff_ns, framedur_ns);
+                       DRM_DEBUG_VBL("crtc %u: Redundant vblirq ignored\n",
+                                     pipe);
        } else {
                /* some kind of default for drivers w/o accurate vbl timestamping */
                diff = in_vblank_irq ? 1 : 0;