Hi Sakari
On Thu, May 23, 2024 at 08:03:49AM GMT, Sakari Ailus wrote:
> Hi Daniel,
[snip]
>
> > +
> > +static int mali_c55_vb2_start_streaming(struct vb2_queue *q, unsigned int count)
> > +{
> > + struct mali_c55_cap_dev *cap_dev = q->drv_priv;
> > + struct mali_c55 *mali_c55 = cap_dev->mali_c55;
> > + struct mali_c55_resizer *rzr = cap_dev->rzr;
> > + struct mali_c55_isp *isp = &mali_c55->isp;
> > + int ret;
> > +
> > + guard(mutex)(&isp->lock);
> > +
> > + ret = pm_runtime_resume_and_get(mali_c55->dev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = video_device_pipeline_start(&cap_dev->vdev,
> > + &cap_dev->mali_c55->pipe);
> > + if (ret) {
> > + dev_err(mali_c55->dev, "%s failed to start media pipeline\n",
> > + mali_c55_cap_dev_to_name(cap_dev));
> > + goto err_pm_put;
> > + }
> > +
> > + mali_c55_cap_dev_stream_enable(cap_dev);
> > + mali_c55_rzr_start_stream(rzr);
> > +
> > + /*
> > + * We only start the ISP if we're the only capture device that's
> > + * streaming. Otherwise, it'll already be active.
> > + */
> > + if (mali_c55->pipe.start_count == 1) {
>
> Do you start streaming on the sensor when the first video node does?
>
> This means that frames may be lost. E.g. the IPU6 ISYS driver only starts
> streaming on the sensor once all video nodes of the pipeline have been
> started.
>
How would you ever know which nodes will be started ?
