Em Sun, 4 Dec 2016 15:25:25 -0300 Ezequiel Garcia <ezequ...@vanguardiasur.com.ar> escreveu:
> On 4 December 2016 at 10:01, Marcel Hasler <mahas...@gmail.com> wrote: > > Hello > > > > 2016-12-03 21:46 GMT+01:00 Ezequiel Garcia <ezequ...@vanguardiasur.com.ar>: > > > >> On 2 December 2016 at 08:05, Mauro Carvalho Chehab > >> <mche...@s-opensource.com> wrote: > >>> Em Sun, 27 Nov 2016 12:11:48 +0100 > >>> Marcel Hasler <mahas...@gmail.com> escreveu: > >>> > >>>> Allow setting a custom record gain for the internal AC97 codec (if > >>>> available). This can be > >>>> a value between 0 and 15, 8 is the default and should be suitable for > >>>> most users. The Windows > >>>> driver also sets this to 8 without any possibility for changing it. > >>> > >>> The problem of removing the mixer is that you need this kind of > >>> crap to setup the volumes on a non-standard way. > >>> > >> > >> Right, that's a good point. > >> > >>> NACK. > >>> > >>> Instead, keep the alsa mixer. The way other drivers do (for example, > >>> em28xx) is that they configure the mixer when an input is selected, > >>> increasing the volume of the active audio channel to 100% and muting > >>> the other audio channels. Yet, as the alsa mixer is exported, users > >>> can change the mixer settings in runtime using some alsa (or pa) > >>> mixer application. > >>> > >> > >> Yeah, the AC97 mixer we are currently leveraging > >> exposes many controls that have no meaning in this device, > >> so removing that still looks like an improvement. > >> > >> I guess the proper way is creating our own mixer > >> (not using snd_ac97_mixer) exposing only the record > >> gain knob. > >> > >> Marcel, what do you think? > >> -- > >> Ezequiel García, VanguardiaSur > >> www.vanguardiasur.com.ar > > > > As I have written before, the recording gain isn't actually meant to > > be changed by the user. In the official Windows driver this value is > > hard-coded to 8 and cannot be changed in any way. And there really is > > no good reason why anyone should need to mess with it in the first > > place. The default value will give the best results in pretty much all > > cases and produces approximately the same volume as the internal 8-bit > > ADC whose gain cannot be changed at all, not even by a driver. > > > > I had considered writing a mixer but chose not to. If the gain setting > > is openly exposed to mixer applications, how do you tell the users > > that the value set by the driver already is the optimal and > > recommended value and that they shouldn't mess with the controls > > unless they really have to? By having a module parameter, this setting > > is practically hidden from the normal user but still is available to > > power-users if they think they really need it. In the end it's really > > just a compromise between hiding it completely and exposing it openly. > > Also, this way the driver guarantees reproducible results, since > > there's no need to remember the positions of any volume sliders. > > > > Hm, right. I've never changed the record gain, and it's true that it > doens't really improve the volume. So, I would be OK with having > a module parameter. > > On the other side, we are exposing it currently, through the "Capture" > mixer control: > > Simple mixer control 'Capture',0 > Capabilities: cvolume cswitch cswitch-joined > Capture channels: Front Left - Front Right > Limits: Capture 0 - 15 > Front Left: Capture 10 [67%] [15.00dB] [on] > Front Right: Capture 8 [53%] [12.00dB] [on] > > So, it would be user-friendly to keep the user interface and continue > to expose the same knob - even if the default is the optimal, etc. > > To be completely honest, I don't think any user is really relying > on any REC_GAIN / Capture setting, and I'm completely OK > with having a mixer control or a module parameter. It doesn't matter. If you're positive that *all* stk1160 use the ac97 mixer the same way, and that there's no sense on having a mixer for it, then it would be ok to remove it. In such case, then why you need a modprobe parameter to allow setting the record level? If this mixer entry is not used, just set it to zero and be happy with that. Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
