Re: [PATCH] drm/sun4i: Fix exclusivity of the TCON clocks

From: Maxime Ripard
Date: Mon Mar 12 2018 - 05:44:53 EST


On Sat, Mar 10, 2018 at 12:05:11PM +0100, megous@xxxxxxxxxx wrote:
> From: Ondrej Jirman <megous@xxxxxxxxxx>
>
> Currently the exclusivity is enabled when the rate is set by
> the mode setting functions. These functions are called by
> mode_set_nofb callback of drm_crc_helper. Then exclusivity
> is disabled when tcon is disabled by atomic_disable
> callback.
>
> What happens is that mode_set_nofb can be called once when
> mode chnages, and afterwards the system can call atomic_enable
> and atomic_disable multiple times without further calls to
> mode_set_nofb.
>
> This happens:
>
> mode_set_nofb - clk exclusivity is enabled
> atomic_enable
> atomic_disable - clk exclusivity is disabled
> atomic_enable
> atomic_disable - clk exclusivity is already disabled, leading to WARN
> in clk_rate_exclusive_put
>
> Solution is to enable exclusivity in sun4i_tcon_channel_set_status.
>
> Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
> Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx>

Applied, thanks!
Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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