2010/9/3 David Henningsson <david.henningsson@xxxxxxxxxxxxx> > 2010-09-02 11:44, Takashi Iwai skrev: > > At Thu, 02 Sep 2010 11:24:45 +0200, > > David Henningsson wrote: > >> > >> 2010-09-02 10:06, Takashi Iwai skrev: > >>> At Wed, 01 Sep 2010 15:26:54 +0200, > >>> David Henningsson wrote: > >>>> > >>>> 2010-08-30 15:08, Takashi Iwai skrev: > >>>>> At Mon, 30 Aug 2010 15:01:29 +0200, > >>>>> David Henningsson wrote: > >>>>>> > >>>>>> 2010-08-30 10:01, Takashi Iwai skrev: > >>>>>>> At Sat, 28 Aug 2010 06:58:20 +0800, > >>>>>>> Raymond Yau wrote: > >>>>>>>> > >>>>>>>> 2010/8/28 David Henningsson <david.henningsson@xxxxxxxxxxxxx> > >>>>>>>> > >>>>>>>>> 2010-08-27 17:43, Clemens Ladisch skrev: > >>>>>>>>>> David Henningsson wrote: > >>>>>>>>>>> So I've discovered that my sound card has a "PCM Playback > Volume" > >>>>>>>>>>> control, but changing that control does not alter the volume. > >>>>>>>>>>> > >>>>>>>>>>> Interestingly enough, this control does not come from the HDA > parser, it > >>>>>>>>>>> is added by alsactl at boot time...! > >>>>>>>>>> > >>>>>>>>>> This control was created by the software volume plugin. When > not using > >>>>>>>>>> this plugin, the control does not have any effect. > >>>>>>>>>> > >>>>>>>>>> To get rid of it, delete its entry from /etc/asound.state. > >>>>>>>>> > >>>>>>>>> Hmm, I wonder if this is an Ubuntu-specific bug then? Because > when I run > >>>>>>>>> Maverick (the upcoming Ubuntu release) from a Live-CD, the "PCM > Playback > >>>>>>>>> Volume" control is still there (and there is no asound.state, > neither in > >>>>>>>>> /etc or in /var/lib/alsa). > >>>>>>>>> When I use the plughw interface, the "PCM Playback Volume" does > not > >>>>>>>>> affect volume output. Should I use another device string to test > the > >>>>>>>>> softvol plugin, to see if it's there or not? > >>>>>>>> > >>>>>>>> The softvol plugin it is defined in "front" device in > >>>>>>>> /usr/share/alsa/cards/HDA-Intel.conf > >>>>>>>> > >>>>>>>> reason is some HDA codec does not has any hardware volume control > (analog) > >>>>>>>> > >>>>>>>> this user-defined control only effective when the application use > "front" > >>>>>>>> device > >>>>>>> > >>>>>>> Hm, but if PA opens the device with SND_PCM_NO_SOFTVOL flag, the > >>>>>>> softvol should be skipped. > >>>>>> > >>>>>> But that does not apply to the mixer controls as well, does it? > >>>>> > >>>>> It does. The mixer element is created when this kind of PCM stream > is > >>>>> opened without SND_PCM_NO_SOFTVOL flag. Then it leaves the control > >>>>> for the later use, and alsactl saves/restores it. So, it's a > chicken- > >>>>> and-egg problem. > >>>> > >>>> Sounds a little strange to me. Thinking in general, if something is > >>>> created when a stream is opened, that something should be destroyed > when > >>>> the stream is closed. > >>> > >>> It's not about the stream-level volume. It's about the global volume. > >>> There have been bunch of machines that have no h/w volume control. > >>> This is the mechanism for such environment. You certainly don't want > >>> to reset the system-level volume at each time you close the stream. > >> > >> So if it's about the global volume it should be created on startup > >> rather than when the stream is opened for the first time. > > > > Ideally yes. But pragmatically, no, it didn't work like that at that > > time. The change had to be seamless. > > > >>>>> Of course, it's possible that it wasn't PA who opened the PCM stream. > >>>>> But, something opened the stream and it created the mixer element. > >>>>> This is the correct behavior. > >>>> > >>>> And once created, it stays there forever... > >>> > >>> Not necessarily forever. It's alsactl who saves/restores the element > >>> > >>>> So even if PA does not > >>>> create it, we'll just transform a persistent problem to an suddenly > >>>> appearing problem? > >>> > >>> Yes, it's just because you started an app that doesn't cope with PA. > >>> And, it's PA who doesn't cope with softvol setup. This is the > >>> conflicting situation. > >> > >> So as I understand it PA should call snd_pcm_open with the > >> SND_PCM_NO_SOFTVOL, which it currently does not. It still puzzles me > >> however how PA manages to open without that flag, which creates a mixer > >> control, and later on that softvol control has no effect. > > > > PA opens the "hw" device in general. This skips the whole things. > > Right, so it tries both, which has the side effect of creating a volume > control, and then prefers hw. > > >>> Now the system doesn't know whether you'll start the non-PA app > >>> again. So, the volume has to be retained. > >>> > >>>> Anyway, do we want softvol at all for HDA? Wouldn't that be such an > >>>> unusual use case, that those people that can't adjust volume any other > >>>> way, can add that softvol themselves in .asoundrc? > >>> > >>> The softvol itself does nothing if the corresponding h/w volume > >>> control exists. It's activated only when the corresponding volume > >>> element is unavailable. > >> > >> Right, but I have a "Master" volume, a "Front" volume, "Headphone" > >> volume and so on, so I have all the HW volumes I need, it's just that > >> none of them happen to be labeled "PCM". > > > > That's the problem. The front playback stream is supposed to have > > a PCM volume control. > > May I kindly ask you to reconsider that statement? AFAIK, for Realtek > chips it is more common not to have a PCM volume control (and I haven't > checked the rest). So that would mean we have tons of bugs in the HDA > driver(s). > > So, this softvol is only useful if all these three conditions are met: > > 1) you're opening "front:x" (or the "surround:x" variants), not > "plughw:x", "hw:x", "default:x", "dmix:x" or anything else. > > 2) you have no playback volume what so ever > > 3) you're not using PA or another sound server with its own software > volume mechanism > > And so far I haven't came across a single HDA that fulfills condition > 2), and I find the combination even more unlikely, but YMMV. > > >>>>>> I think > >>>>>> we still have a problem with PA assuming that it can change the PCM > >>>>>> volume control to change the output volume. > >>>>> > >>>>> PA can check whether it's a user-defined control or not. > >>>> > >>>> Would that be safe - I mean, can't there be user-defined controls PA > >>>> *should* care about? > >>> > >>> It depends on the driver implementation, but as long as PA does > >>> software volume control by itself, and as long as the control elements > >>> are mixer elements, they can be ignored. > >> > >> Interesting. I went looking into the snd_mixer_selem_* documentation (PA > >> uses the simple mixer interface), but I couldn't find a function for > >> determining whether a control is user-defined or not, would you mind > >> pointing me to it? Thanks! > > > > There seems no direct access from the mixer API. > > But you can parse the mixer element to get hcontrol, then snd_ctl_elem > > can be checked for its attribute. > > > > Yeah, a new function could be added for controlling it. > > Or, as an easier option, we can make snd_mixer_open() or > > snd_ctl_open() for skipping the user-defined controls with some flag > > like snd_pcm_open(). > > What would be really helpful would be if snd_mixer_open() took an > optional pcm handle, and then only returned the mixer controls that > affects the signal path of that pcm. > The major problem is PA open "front" by both playback and capture PA should not open "front" for capture The softvol plugin should check the slave pcm (playback/capture) match with the name of the control (Playback Volume/ Capture Volume) There is one control in the alsamixer , but it is unclear that it control both streams or only the recent stream I: module-alsa-sink.c: Using 2 fragments of size 32768 bytes, buffer time is 371.52ms I: module-alsa-sink.c: Time scheduling watermark is 20.00ms D: module-alsa-sink.c: hwbuf_unused_frames=0 D: module-alsa-sink.c: setting avail_min=62005 I: module-alsa-sink.c: Volume ranges from 0 to 39. I: module-alsa-sink.c: Volume ranges from -58.50 dB to 0.00 dB. I: alsa-util.c: ALSA device lacks independant volume controls for each channel. I: module-alsa-sink.c: Using hardware volume control. Hardware dB scale supported. D: alsa-util.c: snd_pcm_dump(): D: alsa-util.c: Soft volume PCM D: alsa-util.c: Control: PCM Playback Volume D: alsa-util.c: min_dB: -51 D: alsa-util.c: max_dB: 0 D: alsa-util.c: resolution: 256 D: alsa-util.c: Its setup is: D: alsa-util.c: stream : PLAYBACK D: alsa-util.c: access : MMAP_INTERLEAVED D: alsa-util.c: format : S16_LE D: alsa-util.c: subformat : STD D: alsa-util.c: channels : 2 D: alsa-util.c: rate : 44100 D: alsa-util.c: exact rate : 44100 (44100/1) D: alsa-util.c: msbits : 16 D: alsa-util.c: buffer_size : 16384 D: alsa-util.c: period_size : 8192 D: alsa-util.c: period_time : 185759 D: alsa-util.c: tstamp_mode : NONE D: alsa-util.c: period_step : 1 D: alsa-util.c: avail_min : 62005 D: alsa-util.c: period_event : 0 D: alsa-util.c: start_threshold : -1 D: alsa-util.c: stop_threshold : -1 D: alsa-util.c: silence_threshold: 0 D: alsa-util.c: silence_size : 0 D: alsa-util.c: boundary : 1073741824 D: alsa-util.c: Slave: Hardware PCM card 1 'HDA Intel' device 0 subdevice 0 D: alsa-util.c: Its setup is: D: alsa-util.c: stream : PLAYBACK D: alsa-util.c: access : MMAP_INTERLEAVED D: alsa-util.c: format : S16_LE D: alsa-util.c: subformat : STD D: alsa-util.c: channels : 2 D: alsa-util.c: rate : 44100 D: alsa-util.c: exact rate : 44100 (44100/1) D: alsa-util.c: msbits : 16 D: alsa-util.c: buffer_size : 16384 D: alsa-util.c: period_size : 8192 D: alsa-util.c: period_time : 185759 D: alsa-util.c: tstamp_mode : NONE D: alsa-util.c: period_step : 1 D: alsa-util.c: avail_min : 62005 D: alsa-util.c: period_event : 0 D: alsa-util.c: start_thresh D: module-alsa-sink.c: Read hardware volume: 0: 100% 1: 100% D: module-alsa-sink.c: Thread starting up D: rtpoll.c: Acquired POSIX realtime signal SIGRTMIN+27 I: module-alsa-sink.c: Starting playback. I: module.c: Loaded "module-alsa-sink" (index: #2; argument: "device_id=1 sink_name=alsa_output.pci_8086_284b_sound_card_0_alsa_playback_0 tsched=1"). D: module-hal-detect.c: Loading module-alsa-source with arguments 'device_id=1 source_name=alsa_input.pci_8086_284b_sound_card_0_alsa_capture_0 tsched=1' D: alsa-util.c: Trying front:1 with SND_PCM_NO_AUTO_FORMAT ... D: alsa-util.c: Maximum hw buffer size is 371 ms I: module-alsa-source.c: Successfully opened device front:1. I: module-alsa-source.c: Successfully enabled mmap() mode. I: module-alsa-source.c: Successfully enabled timer-based scheduling mode. I: (alsa-lib)control.c: Invalid CTL front:1 I: alsa-util.c: Unable to attach to mixer front:1: No such file or directory I: alsa-util.c: Successfully attached to mixer 'hw:1' I: alsa-util.c: Using mixer control "Capture". I: source.c: Created source 3 "alsa_input.pci_8086_284b_sound_card_0_alsa_capture_0" with sample spec s16le 2ch 44100Hz and channel map front-left,front-right I: module-alsa-source.c: Using 2 fragments of size 32768 bytes, buffer time is 371.52ms I: module-alsa-source.c: Time scheduling watermark is 20.00ms D: module-alsa-source.c: hwbuf_unused_frames=0 D: module-alsa-source.c: setting avail_min=62005 I: module-alsa-source.c: Volume ranges from 0 to 54. I: module-alsa-source.c: Volume ranges from -58.50 dB to 22.50 dB. I: alsa-util.c: All 2 channels can be mapped to mixer channels. I: module-alsa-source.c: Using hardware volume control. Hardware dB scale supported. D: alsa-util.c: snd_pcm_dump(): D: alsa-util.c: Soft volume PCM D: alsa-util.c: Control: PCM Playback Volume D: alsa-util.c: min_dB: -51 D: alsa-util.c: max_dB: 0 D: alsa-util.c: resolution: 256 D: alsa-util.c: Its setup is: D: alsa-util.c: stream : CAPTURE D: alsa-util.c: access : MMAP_INTERLEAVED D: alsa-util.c: format : S16_LE D: alsa-util.c: subformat : STD D: alsa-util.c: channels : 2 D: alsa-util.c: rate : 44100 D: alsa-util.c: exact rate : 44100 (44100/1) D: alsa-util.c: msbits : 16 D: alsa-util.c: buffer_size : 16384 D: alsa-util.c: period_size : 8192 D: alsa-util.c: period_time : 185759 D: alsa-util.c: tstamp_mode : NONE D: alsa-util.c: period_step : 1 D: alsa-util.c: avail_min : 62005 D: alsa-util.c: period_event : 0 D: alsa-util.c: start_threshold : -1 D: alsa-util.c: stop_threshold : -1 D: alsa-util.c: silence_threshold: 0 D: alsa-util.c: silence_size : 0 D: alsa-util.c: boundary : 1073741824 D: alsa-util.c: Slave: Hardware PCM card 1 'HDA Intel' device 0 subdevice 0 D: alsa-util.c: Its setup is: D: alsa-util.c: stream : CAPTURE D: alsa-util.c: access : MMAP_INTERLEAVED D: alsa-util.c: format : S16_LE D: alsa-util.c: subformat : STD D: alsa-util.c: channels : 2 D: alsa-util.c: rate : 44100 D: alsa-util.c: exact rate : 44100 (44100/1) D: alsa-util.c: msbits : 16 D: alsa-util.c: buffer_size : 16384 D: alsa-util.c: period_size : 8192 D: alsa-util.c: period_time : 185759 D: alsa-util.c: tstamp_mode : NONE D: alsa-util.c: period_step : 1 D: alsa-util.c: avail_min : 62005 D: alsa-util.c: period_event : 0 D: alsa-util.c: start_threshol D: module-alsa-source.c: Read hardware volume: 0: 62% 1: 62% _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
