Signed-off-by: Aman Gupta <aman@tmm1.net>

Signed-off-by: Aman Gupta <aman@tmm1.net>

Fixes CID 1418358

Signed-off-by: Jorge Ramirez-Ortiz <jramirez@baylibre.com>

During the initialization stage, the codec attempts to get free
buffers from the driver before any have been queued (this is to keep
the code simple and generic)

When the kernel driver detects this situation, it returns POLLERR in
revents and ffmpeg therefore raises a warning.

This commit disables the warning since no buffers were queued to the
driver yet.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>

Qualcomm's db410c/db820 Venus driver currently present in mainline
kernel has a bug which mishandles the CMD_STOP requests causing the
decoder to block while draining [1].

This patch removes the workaround that was used to prevent that
situation.

Encoding/Decoding tested on db820c.

[1] on CMD_STOP, the driver is flushing all buffers and never raising
IPIPE which ends up in blocking on poll.

Fixes a warning on recent Linux:
libavcodec/v4l2_context.c: In function 'ff_v4l2_context_set_status':
libavcodec/v4l2_context.c:496:26: warning: comparison is always false due to limited range of data type

Some V4L2 drivers fail to allocate buffers when sizeimage is not set
to a max value. This is indeed the case for s5p-mfc [1]

Most drivers should be able to calculate this value from the frame
dimensions and format - or at least have their own default.

However since this work around should not impact those drivers doing
the "right thing" this commit just provides such a default.

The calculations were extracted from the v4l2 driver used to develop
the ffmpeg v4l2_m2m support [2]. See venc.c and vdec.c

[1] linux.git/drivers/media/platform/s5p-mfc
[2] linux.git/drivers/media/platform/qcom/venus/

Reviewed-by: Lou Logan <lou@lrcd.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

This patchset enhances Alexis Ballier's original patch and validates
    it using Qualcomm's Venus hardware (driver recently landed upstream
    [1]).

    This has been tested on Qualcomm's DragonBoard 410c and 820c
    Configure/make scripts have been validated on Ubuntu 10.04 and
    16.04.

    Tested decoders:
           - h264
           - h263
           - mpeg4
           - vp8
           - vp9
           - hevc

    Tested encoders:
           - h264
           - h263
           - mpeg4

    Tested transcoding (concurrent encoding/decoding)

    Some of the changes introduced:
        - v4l2: code cleanup and abstractions added
        - v4l2: follow the new encode/decode api.
        - v4l2: fix display size for NV12 output pool.
        - v4l2: handle EOS (EPIPE and draining)
        - v4l2: vp8 and mpeg4 decoding and encoding.
        - v4l2: hevc and vp9 support.
        - v4l2: generate EOF on dequeue errors.
        - v4l2: h264_mp4toannexb filtering.
        - v4l2: fixed make install and fate issues.
        - v4l2: codecs enabled/disabled depending on pixfmt defined
        - v4l2: pass timebase/framerate to the context
        - v4l2: runtime decoder reconfiguration.
        - v4l2: add more frame information
        - v4l2: free hardware resources on last reference being released
        - v4l2: encoding: disable b-frames for upstreaming (patch required)

    [1] https://lwn.net/Articles/697956/

    System Level view:
        v42l_m2m_enc/dec --> v4l2_m2m --> v4l2_context --> v4l2_buffers

    Reviewed-by: Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
    Reviewed-by: Alexis Ballier <aballier@gentoo.org>
    Tested-by: Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>

Signed-off-by: wm4 <nfxjfg@googlemail.com>