[PATCH 1/1] media: Entities with sink pads must have at least one enabled link

[Sylwester Nawrocki]

Hi Sakari,

On 11/13/2012 03:24 PM, Sakari Ailus wrote:
> Hi all,
> 
> Comments would be appreciated, either positive or negative. The omap3isp
> driver does the same check itself currently, but I think this is more
> generic than that.
> 
> Thanks.
> 
> On Fri, Oct 26, 2012 at 10:46:17PM +0300, Sakari Ailus wrote:
>> If an entity has sink pads, at least one of them must be connected to
>> another pad with an enabled link. If a driver with multiple sink pads has
>> more strict requirements the check should be done in the driver itself.
>>
>> Just requiring one sink pad is connected with an enabled link is enough
>> API-wise: entities with sink pads with only disabled links should not be
>> allowed to stream in the first place, but also in a different operation mode
>> a device might require only one of its pads connected with an active link.
>>
>> If an entity has an ability to function as a source entity another logical
>> entity connected to the aforementioned one should be used for the purpose.

Why not leave it to individual drivers ? I'm not sure if it is a good idea
not to allow an entity with sink pads to be used as a source only. It might
be appropriate for most of the cases but likely not all. I'm inclined not to
add this requirement in the API. Just my opinion though.

--
Thanks,
Sylwester