On Tuesday, May 17, 2011 22:05:26 Ondrej Zary wrote: > 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? A fake balance control would be the way to go. There are other drivers that do it like that. > > 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. What typically is done is that the mute v4l2_ctrl pointer is stored and dereferenced to get the value. But in a simple case like this backing up the value works just as well. Regards, Hans > > 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 > > > > -- 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
