On Sun 2017-03-12 07:37:45, Russell King - ARM Linux wrote: > On Sat, Mar 11, 2017 at 07:31:18PM -0800, Steve Longerbeam wrote: > > > > > > On 03/11/2017 10:59 AM, Russell King - ARM Linux wrote: > > >On Sat, Mar 11, 2017 at 10:54:55AM -0800, Steve Longerbeam wrote: > > >> > > >> > > >>On 03/11/2017 10:45 AM, Russell King - ARM Linux wrote: > > >>>I really don't think expecting the user to understand and configure > > >>>the pipeline is a sane way forward. Think about it - should the > > >>>user need to know that, because they have a bayer-only CSI data > > >>>source, that there is only one path possible, and if they try to > > >>>configure a different path, then things will just error out? > > >>> > > >>>For the case of imx219 connected to iMX6, it really is as simple as > > >>>"there is only one possible path" and all the complexity of the media > > >>>interfaces/subdevs is completely unnecessary. Every other block in > > >>>the graph is just noise. > > >>> > > >>>The fact is that these dot graphs show a complex picture, but reality > > >>>is somewhat different - there's only relatively few paths available > > >>>depending on the connected source and the rest of the paths are > > >>>completely useless. > > >>> > > >> > > >>I totally disagree there. Raw bayer requires passthrough yes, but for > > >>all other media bus formats on a mipi csi-2 bus, and all other media > > >>bus formats on 8-bit parallel buses, the conersion pipelines can be > > >>used for scaling, CSC, rotation, and motion-compensated de-interlacing. > > > > > >... which only makes sense _if_ your source can produce those formats. > > >We don't actually disagree on that. > > > > ...and there are lots of those sources! You should try getting out of > > your imx219 shell some time, and have a look around! :) > > If you think that, you are insulting me. I've been thinking about this > from the "big picture" point of view. If you think I'm only thinking > about this from only the bayer point of view, you're wrong. Can you stop that insults nonsense? > Given what Mauro has said, I'm convinced that the media controller stuff > is a complete failure for usability, and adding further drivers using it > is a mistake. Hmm. But you did not present any alternative. Seems some hardware is simply complex. So either we don't add complex drivers (_that_ would be a mistake), or some userspace solution will need to be done. Shell-script running media-ctl does not seem that hard. > So, tell me how the user can possibly use iMX6 video capture without > resorting to opening up a terminal and using media-ctl to manually > configure the pipeline. How is the user going to control the source > device without using media-ctl to find the subdev node, and then using > v4l2-ctl on it. How is the user supposed to know which /dev/video* > node they should be opening with their capture application? Complex hardware sometimes requires userspace configuration. Running a shell script on startup does not seem that hard. And maybe we could do some kind of default setup in kernel, but that does not really solve the problem. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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