Hi Marco On Fri, Aug 19, 2022 at 09:18:32AM +0200, Marco Felsch wrote: > Hi Jacopo, > > thanks for your fast feedback :) > > On 22-08-18, Jacopo Mondi wrote: > > Hi Marco > > > > On Thu, Aug 18, 2022 at 04:47:12PM +0200, Marco Felsch wrote: > > > This is in preparation of switching to the generic dev PM mechanism. > > > Since the .s_power callback will be removed in the near future move the > > > powering into the .s_stream callback. So this driver no longer depends > > > on the .s_power mechanism. > > > > > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > > > > If you want to move to runtime_pm, I would implement it first and have > > s_power call the _resume and _suspend routines, as some platform > > drivers still use s_power() and some of them might depend on it. > > Do we really have platforms which depend on this? IMHO if that is the $ git grep "v4l2_subdev_call(.*, s_power" drivers/media/platform/ | cut -d : -f1 | uniq | wc -l 8 > case than we should fix those platfoms. Since new drivers shouldn't use > this callback anymore. Patches are clearly welcome I guess.. > > In my case, I worked on [1] and wondered why the sensor was enabled > before I told him to do so. Since I didn't implement the s_power() > callback, I had no chance to get enabled before. > I'm not sure I got this part > Can we please decide: > - Do we wanna get rid of the s_power() callback? I think that would be everyone's desire, but drivers have to be moved away from it > - If not, how do we handle those devices then with drivers not > implementing this callback? By maintaining compatibility. I suggested to move to runtime_pm() and wrap _resume/_suspend in s_power(). My understanding is that the two (runtime_pm/s_power) are mutually exclusive, but even if that was not the case, runtime_pm is reference counted, hence as long as calls are balanced this should work, right ? > > [1] https://lore.kernel.org/all/20220818143307.967150-1-m.felsch@xxxxxxxxxxxxxx/ > > > It's a slippery slope.. I would love to get rid of s_power() but if > > any platform uses it with this sensor, it would stop working after > > this change. > > > > > --- > > > drivers/media/i2c/mt9m111.c | 7 ++++++- > > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c > > > index cd74c408e110..8e8ba5a8e6ea 100644 > > > --- a/drivers/media/i2c/mt9m111.c > > > +++ b/drivers/media/i2c/mt9m111.c > > > @@ -1065,7 +1065,6 @@ static const struct v4l2_ctrl_ops mt9m111_ctrl_ops = { > > > }; > > > > > > static const struct v4l2_subdev_core_ops mt9m111_subdev_core_ops = { > > > - .s_power = mt9m111_s_power, > > > .log_status = v4l2_ctrl_subdev_log_status, > > > .subscribe_event = v4l2_ctrl_subdev_subscribe_event, > > > .unsubscribe_event = v4l2_event_subdev_unsubscribe, > > > @@ -1136,8 +1135,14 @@ static int mt9m111_enum_mbus_code(struct v4l2_subdev *sd, > > > static int mt9m111_s_stream(struct v4l2_subdev *sd, int enable) > > > { > > > struct mt9m111 *mt9m111 = container_of(sd, struct mt9m111, subdev); > > > + int ret; > > > > > > mt9m111->is_streaming = !!enable; > > > + > > > + ret = mt9m111_s_power(sd, enable); > > > + if (ret) > > > + return ret; > > > + > > > return 0; > > > } > > > > > > -- > > > 2.30.2 > > > > >
