On Tue, Feb 21, 2017 at 04:03:32PM +0000, Russell King - ARM Linux wrote: > On Tue, Feb 21, 2017 at 05:38:34PM +0200, Sakari Ailus wrote: > > Hi Russell, > > > > On Tue, Feb 21, 2017 at 01:21:32PM +0000, Russell King - ARM Linux wrote: > > > On Tue, Feb 21, 2017 at 02:37:57PM +0200, Sakari Ailus wrote: > > > > Hi Russell, > > > > > > > > On Tue, Feb 21, 2017 at 12:13:32AM +0000, Russell King - ARM Linux wrote: > > > > > On Tue, Feb 21, 2017 at 12:04:10AM +0200, Sakari Ailus wrote: > > > > > > On Wed, Feb 15, 2017 at 06:19:31PM -0800, Steve Longerbeam wrote: > > > > > > > From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> > > > > > > > > > > > > > > Setting and getting frame rates is part of the negotiation mechanism > > > > > > > between subdevs. The lack of support means that a frame rate at the > > > > > > > sensor can't be negotiated through the subdev path. > > > > > > > > > > > > Just wondering --- what do you need this for? > > > > > > > > > > The v4l2 documentation contradicts the media-ctl implementation. > > > > > > > > > > While v4l2 documentation says: > > > > > > > > > > These ioctls are used to get and set the frame interval at specific > > > > > subdev pads in the image pipeline. The frame interval only makes sense > > > > > for sub-devices that can control the frame period on their own. This > > > > > includes, for instance, image sensors and TV tuners. Sub-devices that > > > > > don't support frame intervals must not implement these ioctls. > > > > > > > > > > However, when trying to configure the pipeline using media-ctl, eg: > > > > > > > > > > media-ctl -d /dev/media1 --set-v4l2 '"imx219 pixel 0-0010":0[crop:(0,0)/3264x2464]' > > > > > media-ctl -d /dev/media1 --set-v4l2 '"imx219 0-0010":1[fmt:SRGGB10/3264x2464@1/30]' > > > > > media-ctl -d /dev/media1 --set-v4l2 '"imx219 0-0010":0[fmt:SRGGB8/816x616@1/30]' > > > > > media-ctl -d /dev/media1 --set-v4l2 '"imx6-mipi-csi2":1[fmt:SRGGB8/816x616@1/30]' > > > > > Unable to setup formats: Inappropriate ioctl for device (25) > > > > > media-ctl -d /dev/media1 --set-v4l2 '"ipu1_csi0_mux":2[fmt:SRGGB8/816x616@1/30]' > > > > > media-ctl -d /dev/media1 --set-v4l2 '"ipu1_csi0":2[fmt:SRGGB8/816x616@1/30]' > > > > > > > > > > The problem there is that the format setting for the csi2 does not get > > > > > propagated forward: > > > > > > > > The CSI-2 receivers typically do not implement frame interval IOCTLs as they > > > > do not control the frame interval. Some sensors or TV tuners typically do, > > > > so they implement these IOCTLs. > > > > > > No, TV tuners do not. The frame rate for a TV tuner is set by the > > > broadcaster, not by the tuner. The tuner can't change that frame rate. > > > The tuner may opt to "skip" fields or frames. That's no different from > > > what the CSI block in my example below is capable of doing. > > > > > > Treating a tuner differently from the CSI block is inconsistent and > > > completely wrong. > > > > I agree tuners in that sense are somewhat similar, and they are not treated > > differently because they are tuners (and not CSI-2 receivers). Neither can > > control the frame rate of the incoming video stream. > > > > Conceivably a tuner could implement G_FRAME_INTERVAL IOCTL, but based on a > > quick glance none appears to. Neither do CSI-2 receivers. Only sensor > > drivers do currently. > > Please look again. I am being very careful with "CSI" vs "CSI-2" in my > emails, you are conflating the two. > > In all my emails so far, "CSI" refers to a block of hardware that is > responsible for receiving an image stream from some kind of source. It > contains hardware that supports frame skipping. Ah, I missed the difference. Thanks for pointing it out. Still, that does not change how the skipping would work nor how I proposed it would be configured from the user space. > > "CSI-2" refers to a different block of hardware that is responsible for > receiving a serially encoded stream from a MIPI-CSI-2 compliant source > and providing it to the "CSI" block. > > I would have thought my diagram that I drew would have made it clear that > they were different blocks of hardware, but I guess in this case, the old > saying "a picture is worth 1000 words" is simply not true. > > > Images are transmitted as series of lines, with each line ending in a > > horizontal blanking period, and each frame ending with a similar period of > > I'm sorry, are you seriously teaching me to suck rocks? I am insulted. > > I've been involved in TV and video for many years, I don't need you to > tell me how video is transmitted. > > Sorry, you've just lost my interest in further discussion. There's no need to feel insulted; that certainly was not the intention. I've proposed you a solution, please comment on that. -- Regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
