On Wed, Mar 20, 2024 at 12:33:48AM +0200, Laurent Pinchart wrote: > On Tue, Mar 19, 2024 at 04:20:35PM +0200, Tomi Valkeinen wrote: > > On 19/03/2024 15:27, Sakari Ailus wrote: > > > On Thu, Mar 14, 2024 at 09:30:50AM +0200, Tomi Valkeinen wrote: > > >> On 13/03/2024 09:24, Sakari Ailus wrote: > > >>> Add generic serial metadata mbus formats. These formats describe data > > >>> width and packing but not the content itself. The reason for specifying > > >>> such formats is that the formats as such are fairly device specific but > > >>> they are still handled by CSI-2 receiver drivers that should not be aware > > >>> of device specific formats. What makes generic metadata formats possible > > >>> is that these formats are parsed by software only, after capturing the > > >>> data to system memory. > > >>> > > >>> Also add a definition for "Data unit" to cover what is essentially a pixel > > >>> but is not image data. > > >> > > >> The CCS spec talks about legacy packing and optimized packing for 16+ bit > > >> formats. You cover only the "legacy" ones here. Did you look at those? > > > > > > The reason is that the bus data layout of the new packing at higher bit > > > depth matches with packing at lower bit depths (half to be precise). That's > > > why there's no need to define formats for the new packing methods at higher > > > bit depths (the driver simply uses the packing at half of the bit depth). > > > > Hmm. If we're capturing 10-bit raw format, say, with the width of 640 > > pixels, we'll configure the video stream format according to those. For > > the embedded stream, we'll set it to V4L2_META_FMT_GENERIC_CSI2_10 and > > 640 width, right? > > > > If we're capturing 20-bit raw, we'll configure the video stream format > > again accordingly, width to 640, and 20 bit fourcc/mbus code. If the > > embedded stream uses the "legacy" packing, we'll set the format to > > V4L2_META_FMT_GENERIC_CSI2_20 with width of 640, right? > > > > But if it's using packed format for the embedded stream, we set the > > format to V4L2_META_FMT_GENERIC_CSI2_10 and width to 1280? > > > > Considering that the video and (line-based) embedded data come from the > > same source, I'd expect the widths to be the same. > > I don't have a strong objection against multiplying the width, but we > need to figure out the impact on other kernel space components, as well > as on userspace. I suppose the media bus code for the embedded data > stream on the sensor source pad when using optimized packing and > capturing RAW20 images would be MEDIA_BUS_FMT_META_10 ? In that case I > think the sensor driver should be able to handle the width calculations > on its own, and the value would just be propagated by userspace. This should be documented somewhere in this series by the way (not in this patch). -- Regards, Laurent Pinchart
