From 5278027b3df1a157c7f7d8e3f7e3ba2884aaeee5 Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Sat, 9 Apr 2022 19:57:06 +0100 Subject: 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 Signed-off-by: Kieran Bingham Reviewed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart --- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/gpu/drm/rcar-du') 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; -- cgit v1.2.3