On 01/08/19 10:09, 李夏潤 (Randy Li) wrote: > I sent the other talking about the disadvantage of using buffer tag in > > Re: [PATCHv4 00/10] As was discussed here (among other places) > > > I agree with the buffer tag. But coping from the OUTPUT side to CAPTURE side is a bad idea. > > I think we need a method to refer any buffers when they are allocated. > > When I push a slice with its parameters into the driver, its previous picture in decoded order may not ready yet, using the buffer index, the driver > > is still able to generate the registers table for it. Although you may though it just an additional buffer assignment work before wrote it into the device, > > a few times seeking a buffer in a list. But there is a mode in new generation Rockchip device, called the link mode, you can put a registers into a memory, device would process that register link. You can't interrupt it. That is pretty useful for those codec converting. > > > Besides, I found it is little hard to refer a buffer with different offsets at the same time, it would be used for multiple slices and multiple CTU or filed picture which are not usual case nowadays. > > > Please don't do that. To be honest, I don't understand what the problem is. Can you explain in more detail, perhaps with an example? Does anyone else understand this? Tomasz, I think you've worked with rockchip before, do you see what Randy is referring to? Regards, Hans > > > Randy Li > > *From:* "Hans Verkuil <hverkuil@xxxxxxxxx>" > > *To:* "Linux Media Mailing List <linux-media@xxxxxxxxxxxxxxx>" > > *CC:* "Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>","Maxime Ripard <maxime.ripard@xxxxxxxxxxx>","Tomasz Figa <tfiga@xxxxxxxxxxxx>" > > *Sent:* 2019-01-07 19:36 > > *Subject:* Re: [GIT PULL FOR v5.1] vb2/cedrus: use timestamps to identify buffers[Please note,mail behalf by linux-media-owner@xxxxxxxxxxxxxxx] > > On 01/07/2019 12:30 PM, Hans Verkuil wrote: >> As was discussed here (among other places): >> >>https://lkml.org/lkml/2018/10/19/440 >> >> using capture queue buffer indices to refer to reference frames is >> not a good idea. >> >> Instead, after a long irc discussion: >> >>https://linuxtv.org/irc/irclogger_log/v4l?date=2018-12-12,Wed >> >> it was decided to use the timestamp in v4l2_buffer for this. >> >> However, struct timeval cannot be used in a compound control since >> the size of struct timeval differs between 32 and 64 bit architectures, >> and there are also changes upcoming for y2038 support. >> >> But internally the kernel converts the timeval to a u64 (nsecs since >> boot). So we provide a helper function in videodev2.h that converts >> the timeval to a u64, and that u64 can be used inside compound controls. >> >> In the not too distant future we want to create a new struct v4l2_buffer, >> and then we'll use u64 from the start, so in that case the helper function >> would no longer be needed. >> >> The first three patches add a new m2m helper function to correctly copy >> the relevant data from an output buffer to a capture buffer. This will >> simplify m2m drivers (in fact, many m2m drivers do not do this quite >> right, so a helper function was really needed). >> >> The fourth patch clears up messy timecode documentation that I came >> across while working on this. >> >> Patch 5 adds the new v4l2_timeval_to_ns helper function to videodev2.h. >> The next patch adds the vb2_find_timestamp() function to find buffers >> with a specific u64 timestamp. >> >> Finally the cedrus driver and documentation are updated to use a >> timestamp as buffer identifier. >> >> I also removed the 'pad' fields from the mpeg2 control structs (it >> should never been added in the first place) and aligned the structs >> to a u32 boundary. > > Note that this pull request corresponds with the v6 patch series. > ("[PATCHv6 0/8] vb2/cedrus: use timestamps to identify buffers") > > Regards, > Hans > >> >> Regards, >> >> Hans >> >> The following changes since commit 4bd46aa0353e022c2401a258e93b107880a66533: >> >> media: cx23885: only reset DMA on problematic CPUs (2018-12-20 06:52:01 -0500) >> >> are available in the Git repository at: >> >> git://linuxtv.org/hverkuil/media_tree.git tags/br-buftag >> >> for you to fetch changes up to 690da7b0ab96f6761e72bb0c5c861e1e13acb327: >> >> extended-controls.rst: update the mpeg2 compound controls (2019-01-07 12:23:49 +0100) >> >> ---------------------------------------------------------------- >> Tag branch >> >> ---------------------------------------------------------------- >> Hans Verkuil (8): >> v4l2-mem2mem: add v4l2_m2m_buf_copy_data helper function >> vim2m: use v4l2_m2m_buf_copy_data >> vicodec: use v4l2_m2m_buf_copy_data >> buffer.rst: clean up timecode documentation >> videodev2.h: add v4l2_timeval_to_ns inline function >> vb2: add vb2_find_timestamp() >> cedrus: identify buffers by timestamp >> extended-controls.rst: update the mpeg2 compound controls >> >> Documentation/media/uapi/v4l/buffer.rst | 11 +++++------ >> Documentation/media/uapi/v4l/extended-controls.rst | 28 +++++++++++++++++----------- >> drivers/media/common/videobuf2/videobuf2-v4l2.c | 19 ++++++++++++++++++- >> drivers/media/platform/vicodec/vicodec-core.c | 12 +----------- >> drivers/media/platform/vim2m.c | 12 +----------- >> drivers/media/v4l2-core/v4l2-ctrls.c | 9 --------- >> drivers/media/v4l2-core/v4l2-mem2mem.c | 20 ++++++++++++++++++++ >> drivers/staging/media/sunxi/cedrus/cedrus.h | 9 ++++++--- >> drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 2 ++ >> drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c | 23 +++++++++++------------ >> include/media/mpeg2-ctrls.h | 14 +++++--------- >> include/media/v4l2-mem2mem.h | 20 ++++++++++++++++++++ >> include/media/videobuf2-v4l2.h | 17 +++++++++++++++++ >> include/uapi/linux/videodev2.h | 12 ++++++++++++ >> 14 files changed, 135 insertions(+), 73 deletions(-) >> >
