Re: [PATCH 6/8] omapdrm: hdmi4: refcount hdmi_power_on/off_core

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On 14/04/17 13:25, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> The hdmi_power_on/off_core functions can be called multiple times:
> when the HPD changes and when the HDMI CEC support needs to power
> the HDMI core.
> 
> So use a counter to know when to really power on or off the HDMI core.
> 
> Also call hdmi4_core_powerdown_disable() in hdmi_power_on_core() to
> power up the HDMI core (needed for CEC).
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/gpu/drm/omapdrm/dss/hdmi4.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi4.c b/drivers/gpu/drm/omapdrm/dss/hdmi4.c
> index 4a164dc01f15..e371b47ff6ff 100644
> --- a/drivers/gpu/drm/omapdrm/dss/hdmi4.c
> +++ b/drivers/gpu/drm/omapdrm/dss/hdmi4.c
> @@ -124,14 +124,19 @@ static int hdmi_power_on_core(struct omap_dss_device *dssdev)
>  {
>  	int r;
>  
> +	if (hdmi.core.core_pwr_cnt++)
> +		return 0;
> +

How's the locking between the CEC side and the DRM side? Normally these
functions are protected with the DRM modesetting locks, but CEC doesn't
come from there. We have the hdmi.lock, did you check that it's held
when CEC side calls shared functions?

>  	r = regulator_enable(hdmi.vdda_reg);
>  	if (r)
> -		return r;
> +		goto err_reg_enable;
>  
>  	r = hdmi_runtime_get();
>  	if (r)
>  		goto err_runtime_get;
>  
> +	hdmi4_core_powerdown_disable(&hdmi.core);

I'd like to have the powerdown_disable as a separate patch. Also, now
that you call it here, I believe it can be dropped from hdmi4_configure().

Hmm, but in hdmi4_configure we call hdmi_core_swreset_assert() before
hdmi4_core_powerdown_disable(). I wonder what exactly that does, and
whether we end up resetting also the CEC parts when we change the videomode.

 Tomi


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