Hi Hans, On Tue, Mar 15, 2016 at 12:54:22PM +0100, Hans Verkuil wrote: > On 03/15/16 12:06, Sakari Ailus wrote: > > Hi Philippe, > > > > On Tue, Mar 15, 2016 at 11:14:17AM +0100, Philippe De Muyter wrote: > >> Hi, > >> > >> Sorry if you read the following twice, but the subject of my previous post > >> was not precise enough :( > >> > >> I am in the process of converting a sensor driver compatible with the imx6 > >> freescale linux kernel, to a subdev driver compatible with a current kernel > >> and Steve Longerbeam's work. > >> > >> My sensor can work at any fps (even fractional) up to 60 fps with its default > >> frame size or even higher when using crop or "binning'. That fact is reflected > >> in my previous implemetation of VIDIOC_ENUM_FRAMEINTERVALS, which answered > >> with a V4L2_FRMIVAL_TYPE_CONTINUOUS-type reply. > >> > >> This seem not possible anymore because of the lack of the needed fields > >> in the 'struct v4l2_subdev_frame_interval_enum' used to delegate the question > >> to the subdev driver. V4L2_FRMIVAL_TYPE_STEPWISE does not seem possible > >> anymore either. Has that been replaced by something else or is that > >> functionality not considered relevant anymorea ? > > > > I think the issue was that the CONTINUOUS and STEPWISE were considered too > > clumsy for applications and practically no application was using them, or at > > least the need for these was not seen to be there. They were not added to > > the V4L2 sub-device implementation of the interface as a result. > > It never made sense to me why the two APIs weren't kept the same. > > My suggestion would be to add step_width and step_height fields to > struct v4l2_subdev_frame_size_enum, that way you have the same functionality > back. > > I.e. for discrete formats the min values equal the max values, for continuous > formats the step values are both 1 (or 0 for compability's sake) and the > remainder maps to a stepwise range. On frame intervals... I'm not against changing it if there's a need to. Cc'ing Laurent who I believe wrote the original API. I probably acked it. We just needed to add the type field (snatch one from the reserved array), DISCRETE translates to zero so there are on compatibility issues either. struct v4l2_frmival_stepwise will consume all remaining reserved entries with the exception of one, but there is still room for it. Documentation is needed as well. I don't think it'd be very pretty but I guess there's no way around that at this point. We should have had the which field before the interval field. -- Regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- 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
