[PATCH v2 xf86-video-amdgpu] Don't apply gamma to HW cursor data if colour management is enabled

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

In that case (with DC as of 4.17 kernels), the display hardware applies
gamma to the HW cursor.

v2:
* Also use all 0s when alpha == 0 in the gamma passthrough case.

Bugzilla: https://bugs.freedesktop.org/106578
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/drmmode_display.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index fa0c05b0c..1563417a7 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -1515,6 +1515,17 @@ drmmode_cursor_src_offset(Rotation rotation, int width, int height,
 
 #endif
 
+static uint32_t
+drmmode_cursor_gamma_passthrough(xf86CrtcPtr crtc, uint32_t argb)
+{
+	uint32_t alpha = argb >> 24;
+
+	if (!alpha)
+		return 0;
+
+	return argb;
+}
+
 static uint32_t
 drmmode_cursor_gamma(xf86CrtcPtr crtc, uint32_t argb)
 {
@@ -1525,9 +1536,6 @@ drmmode_cursor_gamma(xf86CrtcPtr crtc, uint32_t argb)
 	if (!alpha)
 		return 0;
 
-	if (crtc->scrn->depth != 24 && crtc->scrn->depth != 32)
-		return argb;
-
 	/* Un-premultiply alpha */
 	for (i = 0; i < 3; i++)
 		rgb[i] = ((argb >> (i * 8)) & 0xff) * 0xff / alpha;
@@ -1544,6 +1552,12 @@ static void drmmode_do_load_cursor_argb(xf86CrtcPtr crtc, CARD32 *image, uint32_
 {
 	ScrnInfoPtr pScrn = crtc->scrn;
 	AMDGPUInfoPtr info = AMDGPUPTR(pScrn);
+	uint32_t (*cursor_gamma)(xf86CrtcPtr crtc, uint32_t argb) =
+		drmmode_cursor_gamma;
+
+	if ((crtc->scrn->depth != 24 && crtc->scrn->depth != 32) ||
+	    drmmode_cm_enabled(&info->drmmode))
+		cursor_gamma = drmmode_cursor_gamma_passthrough;
 
 #if XF86_CRTC_VERSION < 7
 	if (crtc->driverIsPerformingTransform) {
@@ -1559,8 +1573,7 @@ static void drmmode_do_load_cursor_argb(xf86CrtcPtr crtc, CARD32 *image, uint32_
 								      dstx, dsty);
 
 				ptr[dsty * info->cursor_w + dstx] =
-					cpu_to_le32(drmmode_cursor_gamma(crtc,
-									 image[srcoffset]));
+					cpu_to_le32(cursor_gamma(crtc, image[srcoffset]));
 			}
 		}
 	} else
@@ -1570,7 +1583,7 @@ static void drmmode_do_load_cursor_argb(xf86CrtcPtr crtc, CARD32 *image, uint32_
 		int i;
 
 		for (i = 0; i < cursor_size; i++)
-			ptr[i] = cpu_to_le32(drmmode_cursor_gamma(crtc, image[i]));
+			ptr[i] = cpu_to_le32(cursor_gamma(crtc, image[i]));
 	}
 }
 
-- 
2.18.0