Bug 196669
| Summary: | C-Media USB soundcard reports incorrect minimum volume | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Star Brilliant (coder) |
| Component: | Sound(ALSA) | Assignee: | Jaroslav Kysela (perex) |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | bugzilla.kernel.org, coder, tiwai |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 4.11.8 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
lsusb.txt
Test patch Revised fix patch |
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Ignoring the lowest value is no correct solution. We have MINMAX_MUTE type and for the corresponding devices, this type should be used instead. I'm not sure whether it's safe to apply the rule for all C-Media devices. There are tons of C-Media ones, so I'd rather take conservative approach, apply the quirk only to known devices at first. Below is a totally untested patch. Could you check whether it does anything? Created attachment 257927 [details]
Test patch
This patch worked. Thanks. OK, thanks. To be sure, could you give the alsa-info.sh output after the patch? My concern is that whether the quirk is applied to the wrong volumes, not only to the output volumes. Also, do you know other USB device IDs showing the same problem? alsa-info.sh: http://www.alsa-project.org/db/?f=c3b18b819ac85401449bde31f5d734a53ffb66d8 Other volumes: There are 4 volumes in total: - Playback: Speaker - Playback: Mic (which is loopback) - Capture: Mic - Auto Gain Control (boolean, affects both Capture & Playback Mic) For "Playback: Speaker" and "Playback: Mic", the lowest volume acts as muted. For "Capture: Mic", the lowest volume does not act as muted. A quick Google finds me 0d8c:000c also have the same problem: https://unix.stackexchange.com/questions/204782/pulseaudio-with-external-sound-adapter-work-around-broken-sound Related bug report on 0d8c:000c: https://bugzilla.redhat.com/show_bug.cgi?id=1248649 That alsa-info.sh above was captured with the patched kernel. This alsa-info.sh below is captured with the unpatched kernel: http://www.alsa-project.org/db/?f=b807809e8ade21fa3d49e0e890ec778492384070 Thanks. Could you try the revised patch below? If it works, I'm going to submit this and queue for the upstream inclusion. Created attachment 257953 [details]
Revised fix patch
The patch works as intended. Thanks! It's ready to queue for the upstream. Hello. Bug still observed on Ubuntu 18.04 (kernel 4.15.0-39-generic #42-Ubuntu SMP Tue Oct 23 15:48:01 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux). At -27.36dB attenuation, sound is still output (and still very strong). At -27.80dB and below, sound is muted. Device is 0d8c:000c C-Media Electronics, Inc. Audio Adapter. I can post more information if useful (e.g. alsa-info or whatever you ask). Thank you for your attention. A different device, a different problem. Please create another bug report and mention this one there. Thanks. Meanwhile, this particular bug was fixed long time ago in the upstream commit 0f174b3525a43bd51f9397394763925e0ebe7bc7. So let's close. |
Created attachment 257923 [details] lsusb.txt Affected soundcard model: Bus 004 Device 018: ID 0d8c:0014 C-Media Electronics, Inc. USB Mixer: usb_id=0x0d8c0014, ctrlif=0, ctlerr=0 Card: C-Media Electronics Inc. USB Audio Device at usb-0000:00:1d.0-1.2, full speed Unit: 9 Control: name="Speaker Playback Volume", index=0 Info: id=9, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-9472, max=0, dBmin=-3700, dBmax=0 Problem: The soundcard reports -37 dB as the lowest volume to ALSA, but setting the volume to -37 dB mutes the device. This misleading data further prevented the software mixing feature of PulseAudio from working at volume lower than -37 dB (24%), resulting no sound at all. It might be a common hardware problem for all C-Media USB soundcards, although the value "-37" might differ. Suggested workaround: Ignore the reported lowest volume for all 0d8c devices, and set the lowest volume to -Infinity.