Hi Hans, On Monday 13 August 2012 15:13:34 Hans de Goede wrote: [snip] > > 4) What should a driver return in TRY_FMT/S_FMT if the requested format is > > not supported (possible behaviours include returning the currently > > selected format or a default format). > > > > The spec says this: "Drivers should not return an error code unless > > the input is ambiguous", but it does not explain what constitutes an > > ambiguous input. Frankly, I can't think of any and in my opinion > > TRY/S_FMT should never return an error other than EINVAL (if the > > buffer type is unsupported) or EBUSY (for S_FMT if streaming is in > > progress). > > > > Returning an error for any other reason doesn't help the application > > since the app will have no way of knowing what to do next. > > Ack on not returning an error for requesting an unavailable format. As for > what the driver should do (default versus current format) I've no > preference, I vote for letting this be decided by the driver > implementation. That's exactly the point that I wanted to clarify :-) I don't see a good reason to let the driver decide on this, and would prefer returning a default format as TRY_FMT would then always return the same result for a given input format regardless of the currently selected format. -- 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
