Hi Dmitry, Tomasz, On Fri, Jan 3, 2020 at 10:05 PM Dmitry Sepp <dmitry.sepp@xxxxxxxxxxxxxxx> wrote: > > Hi Tomasz, Keiichi, > > On Samstag, 21. Dezember 2019 07:19:23 CET Tomasz Figa wrote: > > On Sat, Dec 21, 2019 at 3:18 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > > On Sat, Dec 21, 2019 at 1:36 PM Keiichi Watanabe <keiichiw@xxxxxxxxxxxx> > wrote: > > > > Hi Dmitry, > > > > > > > > On Sat, Dec 21, 2019 at 12:59 AM Dmitry Sepp > > > > > > > > <dmitry.sepp@xxxxxxxxxxxxxxx> wrote: > > > > > Hi Keiichi, > > > > > > > > > > On Mittwoch, 18. Dezember 2019 14:02:13 CET Keiichi Watanabe wrote: > > > > > > Hi, > > > > > > This is the 2nd version of virtio-video patch. The PDF is available > > > > > > in [1]. > > > > > > The first version was sent at [2]. > > > > > > > > > > > > Any feedback would be appreciated. Thank you. > > > > > > > > > > > > Best, > > > > > > Keiichi > > > > > > > > > > > > [1]: > > > > > > https://drive.google.com/drive/folders/1eT5fEckBoor2iHZR4f4GLxYzFMVa > > > > > > pOFx?us > > > > > > p=sharing [2]: https://markmail.org/message/gc6h25acct22niut > > > > > > > > > > > > Change log: > > > > > > > > > > > > v2: > > > > > > * Removed functionalities except encoding and decoding. > > > > > > * Splited encoder and decoder into different devices that use the > > > > > > same > > > > > > protocol. * Replaced GET_FUNCS with GET_CAPABILITY. > > > > > > * Updated structs for capabilities. > > > > > > > > > > > > - Defined new structs and enums such as image formats, profiles, > > > > > > range > > > > > > > > > > > > (min, max, step), etc > > > > > > > > > > > > * For virtio_video_pixel_format, chose a naming convention that > > > > > > is used > > > > > > > > > > > > in DRM. We removed XBGR, NV21 and I422, as they are not used > > > > > > in the > > > > > > current draft implementation. https://lwn.net/Articles/806416/ > > > > > > > > > > > > - Removed virtio_video_control, whose usage was not documented yet > > > > > > and > > > > > > > > > > > > which is not necessary for the simplest decoding scenario. > > > > > > > > > > > > - Removed virtio_video_desc, as it is no longer needed. > > > > > > > > > > > > * Updated struct virtio_video_config for changes around > > > > > > capabilities. > > > > > > * Added a way to represent supported combinations of formats. > > > > > > > > > > > > - A field "mask" in virtio_video_format_desc plays this role. > > > > > > > > > > > > * Removed VIRTIO_VIDEO_T_STREAM_{START,STOP} because they don't play > > > > > > any > > > > > > meaningful roles. * Removed VIRTIO_VIDEO_T_STREAM_{ATTACH, > > > > > > DETACH}_BACKING > > > > > > and merged them into RESOURCE_{CREATE, DESTROY}. * Added a way to > > > > > > notify/specify resource creation method. > > > > > > > > > > > > - Added a feature flag. > > > > > > - Defined enum virtio_video_mem_type. > > > > > > - Added new fields in video_stream_create. > > > > > > > > > > > > * Modified fields in virtio_video_params. > > > > > > > > > > > > - Added crop information. > > > > > > > > > > > > * Removed enum virtio_video_channel_type because we can get this > > > > > > information by image format. > > > > > > > > > > Could you please explain this? How do you get the information? > > > > > > > > It means that if image formats are well-defined, channel information > > > > (e.g. the order of channels) is uniquely determined. > > > > > > > > > Suppose you have some piece of HW on the host side that wants I420 as > > > > > one > > > > > contig buffer w/ some offsets. But on the driver side, say, gralloc > > > > > gives you three separate buffers, one per channel. How do we pass > > > > > those to the device then? > > > > > > > > You're talking about CrOS use case where buffers are allocated by > > > > virtio-gpu, right? > > > > In this case, virtio-gpu allocates one contiguous host-side buffer and > > > > the client regards a pair of (buffer FD, offset) as one channel. > > > > And, we can register this pair to the device when the buffer is > > > > imported. > > > > In the virtio-vdec spec draft, this pair corresponds to struct > > > > virtio_vdec_plane in struct virtio_vdec_plane. > > > > > > > > So, I suppose we will need similar structs when we add a control to > > > > import buffers. However, I don't think it's necessary when guest pages > > > > are used. > > > > > > I think we need some way for the guest to know whether it can allocate > > > the planes in separate buffers, even when guest pages are used. This > > > would be equivalent to V4L2 M and non-M formats, but mixing this into > > > FourCC in V4L2 is an acknowledged mistake, so we should add a query or > > > something. > > > > > Yes, this is what I mean. In fact, we already do face the situation when the > device side is not happy with the sgt and wants contig. I think we'll add a > module parameter for now. Okay. So, I suppose we'll be able to update structs: * Add a flag in virtio_video_format_desc that indicates whether planes can be in separate buffers, and * Add a flag in virtio_video_format_desc that indicates that the device requires contiguous buffers for this format. Does it make sense? Best regards, Keiichi > > Regards, > Dmitry. > > > > For future V4L2 development we came up with the idea of a format flag > > > which could mean that the hardware allows putting planes in separate > > > buffers. We could have a similar per-format flag in the capabilities, > > > as we already have a list of all the supported formats there. > > > > Sorry, forgot to paste the link from future V4L2 work notes from this year > > ELCE: https://www.spinics.net/lists/linux-media/msg159789.html > > > > > Best regards, > > > Tomasz > > > > > > > Best regards, > > > > Keiichi > > > > > > > > > Best regards, > > > > > Dmitry. > > > > > > > > > > > * Renamed virtio_video_pin to virtio_video_buf_type. > > > > > > > > > > > > - It's similar to V4L2_BUF_TYPE_VIDEO_{OUTPUT, CAPTURE}. > > > > > > > > > > > > * Added an error event. > > > > > > * Reordered some subsections. > > > > > > * Changed styles to make it consistent with other devices. > > > > > > > > > > > > Dmitry Sepp (1): > > > > > > virtio-video: Add virtio video device specification > > > > > > > > > > > > content.tex | 1 + > > > > > > virtio-video.tex | 579 > > > > > > +++++++++++++++++++++++++++++++++++++++++++++++ > > > > > > 2 files changed, 580 insertions(+) > > > > > > create mode 100644 virtio-video.tex > > > > > > > > > > > > -- > > > > > > 2.24.1.735.g03f4e72817-goog > >
