Hi Sylwester, On Wednesday 14 November 2012 10:23:19 Sylwester Nawrocki wrote: > 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. I have mixed feelings about this patch too, which is why I've asked Sakari to cross-post it. It's pretty easy to add this check to the core now, but pushing it back to drivers late if we realize it's too restrictive would be difficult. I think my preference would go for a helper function that drivers can use, possibly first waiting until a second driver requires this kind of checks before implementing it. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
