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Message-ID: <25e5880dc5c2c00bc2c261bd12246289a2adb8b5.camel@kernel.org>
Subject: Re: [PATCH 4/5] drm/vc4: hdmi: Move the HSM clock enable to
 runtime_pm
From:   nicolas saenz julienne <nsaenz@kernel.org>
To:     Maxime Ripard <maxime@cerno.tech>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Daniel Vetter <daniel.vetter@intel.com>,
        David Airlie <airlied@linux.ie>
Cc:     linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
        linux-rpi-kernel@lists.infradead.org,
        Mike Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Michael Stapelberg <michael@stapelberg.ch>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Dave Stevenson <dave.stevenson@raspberrypi.com>
Date:   Thu, 30 Sep 2021 17:54:43 +0200
In-Reply-To: <20210922125419.4125779-5-maxime@cerno.tech>
References: <20210922125419.4125779-1-maxime@cerno.tech>
         <20210922125419.4125779-5-maxime@cerno.tech>
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On Wed, 2021-09-22 at 14:54 +0200, Maxime Ripard wrote:
> In order to access the HDMI controller, we need to make sure the HSM
> clock is enabled. If we were to access it with the clock disabled, the
> CPU would completely hang, resulting in an hard crash.
> 
> Since we have different code path that would require it, let's move that
> clock enable / disable to runtime_pm that will take care of the
> reference counting for us.
> 
> Since we also want to change the HSM clock rate and it's only valid
> while the clock is disabled, we need to move the clk_set_min_rate() call
> on the HSM clock above pm_runtime_get_and_sync().
> 
> Fixes: 4f6e3d66ac52 ("drm/vc4: Add runtime PM support to the HDMI encoder driver")
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> ---

Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Nicolas Saenz Julienne <nsaenz@kernel.org>

Regards,
Nicolas