drm/sun4i: vi scaler: Restore opaque alpha in video modes

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The DE3 mixer initialization clears the entire mixer register space. This
also clears VSU_GLOBAL_ALPHA, despite its hardware reset value being 0xff.

The VI scaler uses Video Normal mode for subsampled YUV formats. In this
mode, VSU_GLOBAL_ALPHA provides the scaler output alpha. Leaving the
register at zero causes the scaler to produce fully transparent output.

Set VSU_GLOBAL_ALPHA to 0xff whenever configuring a DE3 or newer VI
scaler. The register is ignored in UI scaling mode.

Fixes: c50519e6db ("drm/sun4i: Add basic support for DE3")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Chen-Yu Tsai <wens@kernel.org>
Link: https://patch.msgid.link/c48ba85b9e4478d51afde4f36839fd1c1d363b23.1785772659.git.jernej.skrabec@gmail.com
Signed-off-by: Chen-Yu Tsai <wens@kernel.org>

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Jernej Skrabec 2026-08-03 18:10:41 +02:00 • committed by Chen-Yu Tsai

parent 5c31990b21

commit 583d99165a

2 changed files with 3 additions and 0 deletions

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2

drivers/gpu/drm/sun4i/sun8i_vi_scaler.c

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1

drivers/gpu/drm/sun4i/sun8i_vi_scaler.h

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