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authorKieran Bingham <kieran.bingham+renesas@ideasonboard.com>2022-04-09 21:57:06 +0300
committerLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>2022-07-07 05:21:54 +0300
commit5278027b3df1a157c7f7d8e3f7e3ba2884aaeee5 (patch)
treea9b022768e1170a3feb9bfa9fc16be302b5d1617 /drivers/gpu/drm/rcar-du
parentf929217499cf54a30be995aae65e9951ba079c90 (diff)
downloadlinux-5278027b3df1a157c7f7d8e3f7e3ba2884aaeee5.tar.xz
drm: rcar-du: Extend CMM HDSE documentation
When the CMM is enabled, the HDSE offset is further adjusted to compensate for consumed pixels. Explain this further, with an extra comment at the point the offset is adjusted. Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Diffstat (limited to 'drivers/gpu/drm/rcar-du')
-rw-r--r--drivers/gpu/drm/rcar-du/rcar_du_crtc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index f361a604337f..23e1aedf8dc0 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -300,6 +300,11 @@ static void rcar_du_crtc_set_display_timing(struct rcar_du_crtc *rcrtc)
| DSMR_DIPM_DISP | DSMR_CSPM;
rcar_du_crtc_write(rcrtc, DSMR, dsmr);
+ /*
+ * When the CMM is enabled, an additional offset of 25 pixels must be
+ * subtracted from the HDS (horizontal display start) and HDE
+ * (horizontal display end) registers.
+ */
hdse_offset = 19;
if (rcrtc->group->cmms_mask & BIT(rcrtc->index % 2))
hdse_offset += 25;