Hi Steve, On Mon, Feb 20, 2017 at 02:56:15PM -0800, Steve Longerbeam wrote: > > > On 02/20/2017 02:04 PM, Sakari Ailus wrote: > >Hi Steve, > > > >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? > > > Hi Sakari, > > i.MX does need the ability to negotiate the frame rates in the > pipelines. The CSI has the ability to skip frames at the output, > which is something Philipp added to the CSI subdev. That affects > frame interval at the CSI output. > > But as Russell pointed out, the lack of [gs]_frame_interval op > causes media-ctl to fail: > > media-ctl -v -d /dev/media1 --set-v4l2 > '"imx6-mipi-csi2":1[fmt:SGBRG8/512x512@1/30]' > > Opening media device /dev/media1 > Enumerating entities > Found 29 entities > Enumerating pads and links > Setting up format SGBRG8 512x512 on pad imx6-mipi-csi2/1 > Format set: SGBRG8 512x512 > Setting up frame interval 1/30 on entity imx6-mipi-csi2 > Unable to set frame interval: Inappropriate ioctl for device (-25)Unable to > setup formats: Inappropriate ioctl for device (25) > > > So i.MX needs to implement this op in every subdev in the > pipeline, otherwise it's not possible to configure the > pipeline with media-ctl. The frame rate is only set on the sub-device which you explicitly set it. I.e. setting the frame rate fails if it's not supported on a pad. Philipp recently posted patches that add frame rate propagation to media-ctl. Frame rate is typically settable (and gettable) only on sensor sub-device's source pad, which means it normally would not be propagated by the kernel but with Philipp's patches, on the sink pad of the bus receiver. Receivers don't have a way to control it nor they implement the IOCTLs, so that would indeed result in an error. -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
