[PATCH v3 21/22] drm/tilcdc: Initialize crtc->port

[Jyri Sarha]

On 02/23/16 17:19, Tomi Valkeinen wrote:
>
>
> On 23/02/16 17:03, Jyri Sarha wrote:
>> Initialize port device node pointer in the tilcdc crtc. Fixes "Falling
>> back to first CRTC" warning from tda998x driver.
>>
>> The tda998x encoder driver calls drm_of_find_possible_crtcs() to
>> initialize possible_crtcs of struct drm_encoder. The crtc->port needs
>> to be initialized for drm_of_find_possible_crtcs() to work.
>>
>> Signed-off-by: Jyri Sarha <jsarha at ti.com>
>> ---
>>   drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
>> index 248e3ea..1eb4e0e 100644
>> --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
>> +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
>> @@ -124,6 +124,7 @@ static void tilcdc_crtc_destroy(struct drm_crtc *crtc)
>>
>>   	tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
>>
>> +	of_node_put(crtc->port);
>>   	drm_crtc_cleanup(crtc);
>>   	drm_flip_work_cleanup(&tilcdc_crtc->unref_work);
>>
>> @@ -749,6 +750,7 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
>>
>>   struct drm_crtc *tilcdc_crtc_create(struct drm_device *dev)
>>   {
>> +	struct tilcdc_drm_private *priv = dev->dev_private;
>>   	struct tilcdc_crtc *tilcdc_crtc;
>>   	struct drm_crtc *crtc;
>>   	int ret;
>> @@ -775,6 +777,20 @@ struct drm_crtc *tilcdc_crtc_create(struct drm_device *dev)
>>
>>   	drm_crtc_helper_add(crtc, &tilcdc_crtc_helper_funcs);
>>
>> +	if (priv->is_componentized) {
>> +		struct device_node *ports =
>> +			of_get_child_by_name(dev->dev->of_node, "ports");
>> +
>> +		if (ports) {
>> +			crtc->port = of_get_child_by_name(ports, "port");
>> +			of_node_put(ports);
>> +		} else {
>> +			crtc->port =
>> +				of_get_child_by_name(dev->dev->of_node, "port");
>> +		}
>> +		WARN_ON(!crtc->port);
>> +	}
>
> You didn't comment on why this is not an error? Why should the driver
> continue even if crtc->port is missing?
>

At least for the time being if the drm_of_find_possible_crtcs() fails 
the tda998x driver assumes the first crtc with a warning. So for that 
part everything will work just fine still.

Then it is another question how priv->is_componentized could be set and 
probing has gotten this far while there is no port node to be found. The 
WARN_ON() should really never happen as long as the code is the way it 
currently is.

BR,
Jyri