On Tue, Oct 2, 2018 at 8:44 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > On 10/02/18 13:31, Maxime Jourdan wrote: > > For drivers that expose both an OUTPUT queue and > > V4L2_EVENT_SRC_CH_RESOLUTION such as video decoders, it is > > possible that support for this event is limited to a subset > > of the enumerated OUTPUT formats. > > > > This adds V4L2_CID_SUPPORTS_CH_RESOLUTION that allows such a driver to > > notify userspace of per-format support for this event. > > An alternative is a flag returned by ENUMFMT. > > I would definitely invert the flag/control since the default should be > that this event is supported for these types of devices. Instead you > want to signal the exception (not supported). > > I think a format flag is better since this is really tied to the format > for this particular driver. +1 for format flag. It will also make it easier for userspace to enumerate the capabilities. For example, userspace that doesn't want to handle resolution changes on its own (e.g. Chromium), could just discard the formats for which the hardware/firmware doesn't handle them. Best regards, Tomasz
