From:   Christian Hewitt <christianshewitt@gmail.com>
To:     Neil Armstrong <neil.armstrong@linaro.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Kevin Hilman <khilman@baylibre.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        dri-devel@lists.freedesktop.org, linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Christian Hewitt <christianshewitt@gmail.com>
Subject: [PATCH v2] drm/meson: fix 1px pink line on GXM when scaling video overlay
Date:   Fri,  3 Mar 2023 12:33:12 +0000
Message-Id: <20230303123312.155164-1-christianshewitt@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Playing media with a resolution smaller than the crtc size requires the
video overlay to be scaled for output and GXM boards display a 1px pink
line on the bottom of the scaled overlay. Comparing with the downstream
vendor driver revealed VPP_DUMMY_DATA not being set [0].

Setting VPP_DUMMY_DATA prevents the 1px pink line from being seen.

[0] https://github.com/endlessm/linux-s905x/blob/master/drivers/amlogic/amports/video.c#L7869

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Suggested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
---
Change since v1:
This time I sent the right patch from the correct branch; the wording in
v1 is incorrect and the change to meson_registers.h is not required.

 drivers/gpu/drm/meson/meson_vpp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/meson/meson_vpp.c b/drivers/gpu/drm/meson/meson_vpp.c
index 154837688ab0..5df1957c8e41 100644
--- a/drivers/gpu/drm/meson/meson_vpp.c
+++ b/drivers/gpu/drm/meson/meson_vpp.c
@@ -100,6 +100,8 @@ void meson_vpp_init(struct meson_drm *priv)
 			       priv->io_base + _REG(VPP_DOLBY_CTRL));
 		writel_relaxed(0x1020080,
 				priv->io_base + _REG(VPP_DUMMY_DATA1));
+		writel_relaxed(0x42020,
+				priv->io_base + _REG(VPP_DUMMY_DATA));
 	} else if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A))
 		writel_relaxed(0xf, priv->io_base + _REG(DOLBY_PATH_CTRL));
 
-- 
2.34.1