[FFmpeg-devel] [PATCH V2] lavu/qsv: remove the redundant libmfx init code

[Li, Zhong]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Mark
> Thompson
> Sent: Wednesday, September 11, 2019 6:34 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH V2] lavu/qsv: remove the redundant libmfx
> init code
> 
> On 05/09/2019 06:24, Zhong Li wrote:
> > Signed-off-by: Zhong Li <zhong.li at intel.com>
> > ---
> >  libavutil/hwcontext_qsv.c | 24 ++----------------------
> >  1 file changed, 2 insertions(+), 22 deletions(-)
> >
> > diff --git a/libavutil/hwcontext_qsv.c b/libavutil/hwcontext_qsv.c
> > index 0329a81..1c0e4ff 100644
> > --- a/libavutil/hwcontext_qsv.c
> > +++ b/libavutil/hwcontext_qsv.c
> > @@ -1145,27 +1145,6 @@ static int
> > qsv_device_derive_from_child(AVHWDeviceContext *ctx,
> >
> >      err = MFXInit(implementation, &ver, &hwctx->session);
> >      if (err != MFX_ERR_NONE) {
> > -        av_log(ctx, AV_LOG_ERROR, "Error initializing an MFX session: "
> > -               "%d.\n", err);
> > -        ret = AVERROR_UNKNOWN;
> > -        goto fail;
> > -    }
> > -
> > -    err = MFXQueryVersion(hwctx->session, &ver);
> > -    if (err != MFX_ERR_NONE) {
> > -        av_log(ctx, AV_LOG_ERROR, "Error querying an MFX session: %d.\n", err);
> > -        ret = AVERROR_UNKNOWN;
> > -        goto fail;
> > -    }
> > -
> > -    av_log(ctx, AV_LOG_VERBOSE,
> > -           "Initialize MFX session: API version is %d.%d, implementation version
> is %d.%d\n",
> > -           MFX_VERSION_MAJOR, MFX_VERSION_MINOR, ver.Major, ver.Minor);
> > -
> > -    MFXClose(hwctx->session);
> > -
> > -    err = MFXInit(implementation, &ver, &hwctx->session);
> > -    if (err != MFX_ERR_NONE) {
> >          av_log(ctx, AV_LOG_ERROR,
> >                 "Error initializing an MFX session: %d.\n", err);
> >          ret = AVERROR_UNKNOWN;
> > @@ -1182,7 +1161,8 @@ static int
> > qsv_device_derive_from_child(AVHWDeviceContext *ctx,
> >
> >      ret = MFXQueryVersion(hwctx->session,&ver);
> >      if (ret == MFX_ERR_NONE) {
> > -        av_log(ctx, AV_LOG_VERBOSE, "MFX compile/runtime
> API: %d.%d/%d.%d\n",
> > +        av_log(ctx, AV_LOG_VERBOSE,
> > +               "Initialize MFX session: API version is %d.%d,
> > + implementation version is %d.%d\n",
> >                 MFX_VERSION_MAJOR, MFX_VERSION_MINOR, ver.Major, ver.Minor);
> >      }
> >      return 0;
> >
> 
> Can you add some more explanation?  The extra session checking the version is
> not obviously redundant, and the commit log does indicate that the setup was
> deliberate:
> 
> commit ccbb31c14b766ef666ef2daa8c467e478183a957
> Author: Luca Barbato <lu_zero at gentoo.org>
> Date:   Mon Sep 25 09:57:30 2017 +0000
> 
>     qsv: Make sure the session is set with the latest version
> 
>     It is needed to have the calls to MFXJoinSession succeed.
> 
> 
> - Mark

Thanks to point out this. 
So probably just need to remove the redundant MFXQueryVersion()? 
Will update the patch.