[PATCH 6.1 116/127] drm/imx/ipuv3: Fix front porch adjustment upon hactive aligning

Greg Kroah-Hartman
2023-08-09T10:56:34Z

From: Alexander Stein <alexander.stein@ew.tq-group.com>

[ Upstream commit ee31742bf17636da1304af77b2cb1c29b5dda642 ]

When hactive is not aligned to 8 pixels, it is aligned accordingly and
hfront porch needs to be reduced the same amount. Unfortunately the front
porch is set to the difference rather than reducing it. There are some
Samsung TVs which can't cope with a front porch of instead of 70.

Fixes: 94dfec48fca7 ("drm/imx: Add 8 pixel alignment fix")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20230515072137.116211-1-alexander.stein@ew.tq-group.com
[p.zabel@pengutronix.de: Fixed subject]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230515072137.116211-1-alexander.stein@ew.tq-group.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/imx/ipuv3-crtc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index 5f26090b0c985..89585b31b985e 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -310,7 +310,7 @@ static void ipu_crtc_mode_set_nofb(struct drm_crtc *crtc)
dev_warn(ipu_crtc->dev, "8-pixel align hactive %d -> %d\n",
sig_cfg.mode.hactive, new_hactive);

- sig_cfg.mode.hfront_porch = new_hactive - sig_cfg.mode.hactive;
+ sig_cfg.mode.hfront_porch -= new_hactive - sig_cfg.mode.hactive;
sig_cfg.mode.hactive = new_hactive;
}

--
2.40.1