On 03/19/2017 01:14 PM, Russell King - ARM Linux wrote: > On Sat, Mar 18, 2017 at 12:58:27PM -0700, Steve Longerbeam wrote: >> On 03/18/2017 12:22 PM, Russell King - ARM Linux wrote: >>> 0:00:01.955927879 20954 0x15ffe90 INFO v4l2 gstv4l2object.c:3811:gst_v4l2_object_get_caps:<v4l2src0> probed caps: video/x-bayer, format=(string)rggb, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)I420, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)YV12, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)BGR, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1; video/x-raw, format=(string)RGB, framerate=(fraction)30000/1001, width=(int)816, height=(int)616, interlace-mode=(string)progressive, pixel-aspect-ratio=(fraction)1/1 >>> >>> despite the media pipeline actually being configured for 60fps. >>> >>> Forcing it by adjusting the pipeline only results in gstreamer >>> failing, because it believes that v4l2 is unable to operate at >>> 60fps. >>> >>> Also note the complaints from v4l2src about the non-compliance... >> >> Thanks, I've fixed most of v4l2-compliance issues, but this is not >> done yet. Is that something you can help with? > > I've looked at this, and IMHO it's yet another media control API mess. > > - media-ctl itself allows setting the format on subdev pads via > struct v4l2_subdev_format. > > - struct v4l2_subdev_format contains a struct v4l2_mbus_framefmt. > > - struct v4l2_mbus_framefmt contains: > * @width: frame width > * @height: frame height > * @code: data format code (from enum v4l2_mbus_pixelcode) > * @field: used interlacing type (from enum v4l2_field) > * @colorspace: colorspace of the data (from enum v4l2_colorspace) > * @ycbcr_enc: YCbCr encoding of the data (from enum v4l2_ycbcr_encoding) > * @quantization: quantization of the data (from enum v4l2_quantization) > * @xfer_func: transfer function of the data (from enum v4l2_xfer_func) > > - media-ctl sets width, height, code and field, but nothing else. > > We're already agreed that the fields that media-ctl are part of the > format negotiation between the ultimate source, flowing down to the > capture device. However, there's no support in media-ctl to deal > with these other fields - so media-ctl in itself is only half- > implemented. Correct. The colorspace et al fields are in practice unimportant for sensors. For HDMI/DP they are very important, though. It's the reason why nobody worked on adding support for this to media-ctl, it's almost exclusively used with sensors. Not saying that it is right that it hasn't been added to media-ctl, just that it never had a high enough prio. Regards, Hans > > From what I can tell, _we_ are doing the right thing in imx-media-capture. > > However, I think part of the problem is the set_fmt implementation. > When a source pad is configured via set_fmt(), any fields that can > not be altered (eg, because the subdev doesn't support colorspace > conversion) need to be preserved from the subdev's sink pad. > > Right now, CSI doesn't do that - it only looks at the width, height, > code, and field. > > I think we've got other bugs though that haven't been picked up by any > review - csi_try_fmt() adjusts the format using the _current_ > configuration of the sink pad, even when using V4L2_SUBDEV_FORMAT_TRY. > This seems wrong according to the docs: the purpose of the try > mechanism is to be able to setup the _entire_ pipeline using the TRY > mechanism to work out whether the configuration works, before then > setting for real. If we're validating the TRY formats against the > live configuration, then we're not doing that. > > There's calls for: > > v4l2_subdev_get_try_format > v4l2_subdev_get_try_crop > v4l2_subdev_get_try_compose > > to get the try configuration - we hardly make use of all of these. I > would suggest that we change the approach to implementing the various > subdevs such that: > > 1) like __csi_get_fmt(), we have accessors that gets a pointer to the > correct state for the TRY/live settings. > > 2) everywhere we're asked to get or set parameters that can be TRY/live, > we use these accessors to retrieve a pointer to the correct state to > not only read, but also modify. > > 3) when we're evaluating parameters against another pad, we use these > accessors to obtain the other pad's configuration, rather than poking > about in the state saved in the subdev's priv-> (which is irrelevant > for the TRY variant.) > > 4) ensure that all parameters which the subdev itself does not support > modification of are correctly propagated from the sink pad to all > source pads, and are unable to be modified via the source pad. > _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
