Re: [PATCH] drm/amd/pm: Fix incorrect avg vcn utilization in gpu_metrics

[Alex Deucher]

On Thu, Aug 13, 2026 at 5:36 PM Boqun Feng <boqun@xxxxxxxxxx> wrote:
>
> On Wed, Aug 05, 2026 at 07:02:21AM -0700, Boqun Feng wrote:
> > In a Strix Halo system, a >100 average_vcn_activity in gpu_metrics can
> > be observed by running the following command:
> >
> >     ffmpeg -hwaccel vappi -vappi_device /dev/dri/renderD128 -i \
> >     ~/sample-10s.mp4 -vf hwupload,scale_vappi=format=nv12 -c:v \
> >     h264_vappi /tmp/output.mp4
> >
> > This is incorrect because the value is supposed to be in [0-100] range.
> >
> > The cause of the issue is that the metrics.VcnActivity reported by
> > smu_cmn_get_metrics_table() is a permyriad value instead of a percentage
> > value (e.g. smu_v14_0_0_get_smu_metrics_data() has a division by 100 to
> > report the vcn_busy_percent). Therefore fix this by applying the same
> > division in smu_v14_0_0_get_gpu_metrics().

I think this is correct as is.  smu_v14_0_0_get_smu_metrics_data() is
used to fetch data for standardized formats like hwmon while
smu_v14_0_0_get_gpu_metrics() is for dumping the raw metrics data.

Alex

> >
> > Reported-by: Mark Janes <mjanes@xxxxxxxxxxx>
> > Signed-off-by: Boqun Feng <boqun@xxxxxxxxxx>
>
> Ping?
>
> Regards,
> Boqun
>
> > ---
> >  drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c
> > index 568665265a13..1058338344b0 100644
> > --- a/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c
> > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c
> > @@ -566,7 +566,8 @@ static ssize_t smu_v14_0_0_get_gpu_metrics(struct smu_context *smu,
> >       gpu_metrics->temperature_skin = metrics.SkinTemp;
> >
> >       gpu_metrics->average_gfx_activity = metrics.GfxActivity;
> > -     gpu_metrics->average_vcn_activity = metrics.VcnActivity;
> > +     /* metrics.VcnActivity is permyriad, convert it to percentage. */
> > +     gpu_metrics->average_vcn_activity = metrics.VcnActivity / 100;
> >       memcpy(&gpu_metrics->average_ipu_activity[0],
> >               &metrics.IpuBusy[0],
> >               sizeof(uint16_t) * 8);
> > --
> > 2.50.1 (Apple Git-155)
> >