From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Cc: dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com,
David Airlie <airlied@linux.ie>, Chen-Yu Tsai <wens@csie.org>
Subject: Re: [PATCH] drm/sun4i: tcon: Prepare and enable TCON channel 0 clock at init
Date: Fri, 1 Feb 2019 14:12:18 +0100 [thread overview]
Message-ID: <20190201131218.633gv3npsekliezj@flea> (raw)
In-Reply-To: <20190131132550.26355-1-paul.kocialkowski@bootlin.com>
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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@bootlin.com>
Applied, thanks!
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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prev parent reply other threads:[~2019-02-01 13:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-31 13:25 [PATCH] drm/sun4i: tcon: Prepare and enable TCON channel 0 clock at init Paul Kocialkowski
2019-02-01 13:12 ` Maxime Ripard [this message]
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