From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Longerbeam Subject: Re: [PATCH v5 18/39] [media] v4l: subdev: Add function to validate frame interval Date: Sat, 11 Mar 2017 12:31:24 -0800 Message-ID: References: <1489121599-23206-1-git-send-email-steve_longerbeam@mentor.com> <1489121599-23206-19-git-send-email-steve_longerbeam@mentor.com> <20170311134119.GO3220@valkosipuli.retiisi.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170311134119.GO3220-S+BSfZ9RZZmRSg0ZkenSGLdO1Tsj/99ntUK59QYPAWc@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sakari Ailus Cc: robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, fabio.estevam-3arQi8VN3Tc@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, mchehab-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org, nick-gcszYUEDH4VrovVCs/uTlw@public.gmane.org, markus.heiser-O6JHGLzbNUwb1SvskN2V4Q@public.gmane.org, p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, laurent.pinchart+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, bparrot-l0cyMroinI0@public.gmane.org, geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, minghsiu.tsai-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, tiffany.lin-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, jean-christophe.trotin-qxv4g6HH51o@public.gmane.org, horms+renesas-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org, niklas.soderlund+renesas-1zkq55x86MTxsAP9Fp7wbw@public.gmane.org, robert.jarzmik-GANU6spQydw@public.gmane.org, songjun.wu-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org, andrew-ct.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-me List-Id: devicetree@vger.kernel.org On 03/11/2017 05:41 AM, Sakari Ailus wrote: > Hi Steve, > > On Thu, Mar 09, 2017 at 08:52:58PM -0800, Steve Longerbeam wrote: >> If the pads on both sides of a link specify a frame interval, then >> those frame intervals should match. Create the exported function >> v4l2_subdev_link_validate_frame_interval() to verify this. This >> function can be called in a subdevice's media_entity_operations >> or v4l2_subdev_pad_ops link_validate callbacks. >> >> Signed-off-by: Steve Longerbeam > > If your only goal is to configure frame dropping on a sub-device, I suggest > to implement s_frame_interval() on the pads of that sub-device only. The > frames are then dropped according to the configured frame rates between the > sink and source pads. Say, configuring sink for 1/30 s and source 1/15 would > drop half of the incoming frames. > > Considering that supporting specific frame interval on most sub-devices adds > no value or is not the interface through which it the frame rate configured, > I think it is overkill to change the link validation to expect otherwise. Well, while I think this function might still have validity in the future, I do agree with you that a subdev that has no control over frame rate has no business implementing the get|set ops. In the imx-media subdevs, the only one that can affect frame rate (via frame skipping) is the CSI. So I'll go ahead and remove the [gs]_frame_interval ops from the others. I can remove this patch as a result. Steve -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html