Hi Tomasz, On Fri, May 25, 2018 at 03:18:38PM +0900, Tomasz Figa wrote: > On Fri, May 25, 2018 at 5:47 AM Sakari Ailus <sakari.ai...@linux.intel.com> > wrote: > > > Hi Jacopo, > > > On Thu, May 24, 2018 at 10:07:38PM +0200, jacopo mondi wrote: > > ... > > > > > about that, but I wonder why setting controls should be enabled only > > > > > when streaming. I would have expected runtime_pm_get/put in > subdevices > > > > > node open/close functions not only when streaming. Am I missing > something? > > > > > > > > You can do it either way. If powering on the sensor takes a long > time, then > > > > doing that in the open callback may be helpful as the user space has > a way > > > > to keep the device powered. > > > > > > Ok, so I assume my comment could be ignored, assuming is fine not > > > being able to set control if the sensor is not streaming. Is it? > > > I'd say so. From the user's point of view, the sensor doesn't really do > > anything when it's in software standby mode. > > Just to make sure we're on the same page, the code actually does nothing > when the sensor is not in streaming mode (i.e. powered off). When stream is > being started, the V4L2 control framework will call s_ctrl for all the > controls in the handler to synchronize hardware state and this is when all > the controls set before powering on will actually be programmed into the > hardware registers.
Thanks, I had missed that part. I quickly tried searching for 's_ctrl' calls in the v4l2-core/ code and I've found nothing that invokes that in response to a streaming start operation. Just if you happen to have any reference handy, could you please point me to that part, just for my better understanding? Thanks j > > Best regards, > Tomasz
signature.asc
Description: PGP signature
