On Tuesday 17 May 2011 21:33:14 Hans Verkuil wrote: > Hi Ondrej! > > On Sunday, May 15, 2011 23:26:33 Hans Verkuil wrote: > > On Sunday, May 15, 2011 22:18:21 Ondrej Zary wrote: > > > Thanks, it's much simpler with the new control framework. > > > Do the negative volume control values make sense? The TC9154A chip can > > > attenuate the volume from 0 to -68dB in 2dB steps. > > > > It does make sense, but I think I would offset the values so they start > > at 0. Mostly because there might be some old apps that set the volume to > > 0 when they want to mute, which in this case is full volume. > > > > I am not aware of any driver where a volume of 0 isn't the same as the > > lowest volume possible, so in this particular case I would apply an > > offset. > > > > I will have to do a closer review tomorrow or the day after. I think > > there are a few subtleties that I need to look at. Ping me if you haven't > > heard from me by Wednesday. I would really like to get these drivers up > > to spec now that I have someone who can test them, and once that's done I > > hope that I never have to look at them again :-) (Unlikely, but one can > > dream...) > > OK, I looked at it a bit more and it needs to be changed a little bit. The > problem is that the VOLUME control is added after snd_tea575x_init, i.e. > after the video_register_device call. The video_register_device call should > be the last thing done before the init sequence returns. There may be > applications (dbus/hal) that open devices as soon as they appear, so doing > more initialization after the video node is registered is not a good idea > (many older V4L drivers make this mistake). > > Perhaps creating a snd_tea575x_register function doing just the > registration may be a good idea. Or a callback before doing the > video_register_device. OK, I'll reorder the lines in snd_tea575x_init function and add a callback that radio-sf16fmr2 can use. Also upgraded my card with TC9154AP chip so I can actually test the volume control code (and it was broken in my previous patch...). The left and right channels can be separately controlled - is there a way to provide separate left and right volume controls? Or do I need to fake up a balance control? > Another thing: the tea->mute field shouldn't be needed anymore. And the > 'mute on init' bit in snd_tea575x_init can be removed as well since that > is automatically performed by v4l2_ctrl_handler_setup. Thought about this too but the snd_tea575x_write() and snd_tea575x_read() functions need to know the mute status. And these functions are also used to detect the tuner presence before initializing the controls. I don't see any elegant solution. > In addition, the .ioctl field in tea575x_fops can be replaced by > .unlocked_ioctl. The whole exclusive open stuff and the in_use field can be > removed. The only thing needed is a struct mutex in struct snd_tea575x, > initialize it and set tea575x_radio_inst->lock to the mutex. This will > serialize all access safely. I'll do this as a separate patch later. > To do this really right you should add struct v4l2_device to struct > snd_tea575x (the radio-sf16fmr2 driver has one, so you can use that as an > example). With that in place you can also add support for 'priority' > handling. I'd say see what you can do, and if it takes too much time then > mail me the tea575x code and the radio-sf16frm2 code and I'll finish it. > > Regards, > > Hans -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
