Hi Changhuang,
On Jun 28, 2024 at 08:45:06 +0000, Changhuang Liang wrote:
> Hi Tomi,
>
> [...]
> > > +static int csi2rx_suspend(struct device *dev) {
> > > + struct csi2rx_priv *csi2rx = dev_get_drvdata(dev);
> > > +
> > > + mutex_lock(&csi2rx->lock);
> > > + if (csi2rx->count)
> > > + csi2rx_stop(csi2rx);
> > > + mutex_unlock(&csi2rx->lock);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int csi2rx_resume(struct device *dev) {
> > > + struct csi2rx_priv *csi2rx = dev_get_drvdata(dev);
> > > +
> > > + mutex_lock(&csi2rx->lock);
> > > + if (csi2rx->count)
> > > + csi2rx_start(csi2rx);
> > > + mutex_unlock(&csi2rx->lock);
> > > + return 0;
> > > +}
> > > +
> >
> > I don't think this looks correct. Afaik the runtime suspend/resume is not called
> > on system suspend/resume. You could change the SET_RUNTIME_PM_OPS to
> > use the same callbacks for runtime and system suspend, but I think that's a
> > bad idea. Runtime suspend is not supposed to turn off the streaming. The
> > driver is supposed to turn off the streaming, then call runtime_put, which
> > would result in runtime suspend callback getting called.
> >
>
> I implemented system suspend/resume based on this patch, I feel good about it.
>
> https://lore.kernel.org/all/20240326031237.25331-1-changhuang.liang@xxxxxxxxxxxxxxxx/
Thanks for carrying this patch in your series.
I think Tomi's point still holds - only the system suspend hook should
try to stop/start the CSI2RX device.
Runtime PM hooks are usually only called when there are no users, so no
active streams.
>
> Regards,
> Changhuang
--
Thanks,
Jai
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