Hi Andrey,
On Fri, Aug 18, 2023 at 08:34:16PM +0300, Andrey Skvortsov wrote:
> If system was suspended while camera sensor was used, data and
> interrupts were still coming from sensor and that caused unstable
> system. Sometimes system hanged during a resume. Use
> pm_runtime_force_* helpers in order to support system suspend.
>
> Signed-off-by: Andrey Skvortsov <[email protected]>
Thanks for the patch.
It's not been documented really how system suspend and resume should
work for complex cameras. But I don't think it can be done by drivers
separately as the CSI-2 bus initialisation requires actions from both
sender and receiver drivers, at particular points of time.
So I think we'll need to initiate this from the driver handling DMA, just
as starting and stopping streaming. Even then, there needs to be a
certainty that the sensor device has resumed before streaming is started. I
recall Laurent suggested device links for that purpose, but I don't think
any work has been done to implement it that way.
--
Kind regards,
Sakari Ailus