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. Best regards, Tomasz
