[PATCH 1/1] drm/imx/ipuv-v3: Fix front porch adjustment upon hactive aligning

[Alexander Stein]

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 at ew.tq-group.com>
---
AFAICS ipu_di_adjust_videomode() checks that front porch is big enough to
reduce the alignment difference.

 drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
index 1d306f7be9fd..341e9125bf2c 100644
--- a/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
@@ -311,7 +311,7 @@ static void ipu_crtc_mode_set_nofb(struct drm_crtc *crtc)
 			 sig_cfg.mode.hactive, new_hactive);
 
 		dev_info(ipu_crtc->dev, "hfront_porch: %u\n", sig_cfg.mode.hfront_porch);
-		sig_cfg.mode.hfront_porch = new_hactive - sig_cfg.mode.hactive;
+		sig_cfg.mode.hfront_porch -= new_hactive - sig_cfg.mode.hactive;
 		dev_info(ipu_crtc->dev, "hfront_porch: %u\n", sig_cfg.mode.hfront_porch);
 		sig_cfg.mode.hactive = new_hactive;
 	}
-- 
2.34.1