[PATCH 23/33] drm/vc4: hdmi: Move HDMI reset to pm_resume

[Florian Fainelli]

On 6/13/22 07:47, Maxime Ripard wrote:
> From: Dave Stevenson <dave.stevenson at raspberrypi.com>
> 
> The BCM2835-37 found in the RaspberryPi 0 to 3 have a power domain
> attached to the HDMI block, handled in Linux through runtime_pm.
> 
> That power domain is shared with the VEC block, so even if we put our
> runtime_pm reference in the HDMI driver it would keep being on. If the
> VEC is disabled though, the power domain would be disabled and we would
> lose any initialization done in our bind implementation.
> 
> That initialization involves calling the reset function and initializing
> the CEC registers.
> 
> Let's move the initialization to our runtime_resume implementation so
> that we initialize everything properly if we ever need to.
> 
> Fixes: c86b41214362 ("drm/vc4: hdmi: Move the HSM clock enable to runtime_pm")
> Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.com>
> Signed-off-by: Maxime Ripard <maxime at cerno.tech>

After seeing the same warning as Stefan reported in the link below, but 
on the Raspberry Pi 4B:

https://www.spinics.net/lists/dri-devel/msg354170.html

a separate bisection effort led me to this commit, before is fine, after 
produces 4 warnings during boot, see attached log.

Is there a fix that we can try that would also cover the Raspberry Pi 
4B? Is it possible that this series precipitates the problem:

https://www.spinics.net/lists/arm-kernel/msg984638.html
-- 
Florian
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