drm/sun4i: backend: Add comment explaining why registers are cleared

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Many of the backend's layer configuration registers have undefined
default values. This poses a risk as we use regmap_update_bits in
some places, and don't overwrite the whole register.

At probe/bind time we explicitly clear all the control registers
by writing 0 to them. This patch adds a more detailed explanation
on why we're doing this.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171014040252.9621-5-wens@csie.org

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Chen-Yu Tsai 2017-10-14 12:02:49 +08:00 • committed by Maxime Ripard

parent cff2192f80

commit 936598d16e

1 changed files with 8 additions and 1 deletions

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drivers/gpu/drm/sun4i/sun4i_backend.c

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