Re: [PATCH] drm/sun4i: tcon: Prepare and enable TCON channel 0 clock at init

From: Maxime Ripard
Date: Fri Feb 01 2019 - 08:12:23 EST


On Thu, Jan 31, 2019 at 02:25:50PM +0100, Paul Kocialkowski wrote:
> When initializing clocks, a reference to the TCON channel 0 clock is
> obtained. However, the clock is never prepared and enabled later.
> Switching from simplefb to DRM actually disables the clock (that was
> usually configured by U-Boot) because of that.
>
> On the V3s, this results in a hang when writing to some mixer registers
> when switching over to DRM from simplefb.
>
> Fix this by preparing and enabling the clock when initializing other
> clocks. Waiting for sun4i_tcon_channel_enable to enable the clock is
> apparently too late and results in the same mixer register access hang.
>
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>

Applied, thanks!
Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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