drm/i915: Fix cursor updates on some platforms

[karo-tx-linux.git] / drivers / gpu / drm / i915 / intel_display.c

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index dec9e58545a111b6f8d5aa9957c924d9e2ebcf16..ae4fb72a3394ba7736344e21ddb8b7f281019811 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9540,7 +9540,16 @@ static void i9xx_update_cursor(struct intel_plane *plane,
         * On some platforms writing CURCNTR first will also
         * cause CURPOS to be armed by the CURBASE write.
         * Without the CURCNTR write the CURPOS write would
-        * arm itself.
+        * arm itself. Thus we always start the full update
+        * with a CURCNTR write.
+        *
+        * On other platforms CURPOS always requires the
+        * CURBASE write to arm the update. Additonally
+        * a write to any of the cursor register will cancel
+        * an already armed cursor update. Thus leaving out
+        * the CURBASE write after CURPOS could lead to a
+        * cursor that doesn't appear to move, or even change
+        * shape. Thus we always write CURBASE.
         *
         * CURCNTR and CUR_FBC_CTL are always
         * armed by the CURBASE write only.
@@ -9559,6 +9568,7 @@ static void i9xx_update_cursor(struct intel_plane *plane,
                plane->cursor.cntl = cntl;
        } else {
                I915_WRITE_FW(CURPOS(pipe), pos);
+               I915_WRITE_FW(CURBASE(pipe), base);
        }
 
        POSTING_READ_FW(CURBASE(pipe));