Hi Stephan, On Wed, 2017-08-23 at 13:25 +0200, Stephan Bauroth wrote: > Dear List, > > I'm trying to directly output a captured video signal to an LVDS > panel > on an imx6q. Capturing frames works fine using the staging imx-media > driver. I can grab JPGs using v4l2grab and I can stream the input to > the > display with gstreamer. However, when streaming, one of the cores is > utilized by ~66%, and I have to use the videoconvert module of > gstreamer. > > The IPU in imx6 can directly stream an captured signal back to the > display processor (DP) according to [1]. While the capturing paths > within the IPU are managed by the staging media-imx driver, its > output > paths are not, so I can not simply set up links using media-ctl. We do not support the direct CSI -> DP path because that requires synchronised clocks between sensor and display. But it is possible to stream buffers through system RAM without much CPU involvement using the dmabuf mechanism. > So, my question is whether it is possible to hook up the captured > signal > to the DP using either the ipuv3 driver or the frame buffer driver > (mxcfb) or something else, and if yes, how? > > Thanks for any help and/or hints > Stephan > > [1] http://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf, pg. > 2732 > or chapter 37.1.2.1.4.1, 'Camera Preview' To avoid CPU copies, you'd have to transfer dmabufs from the V4L2 capture device to the DRM output. On current GStreamer this can be achieved with a pipeline like: v4l2src io-mode=dmabuf ! kmssink regards Philipp
