Mauro,
thanks for the report and sorry for the make problem.
Could you try below debug patch? I add more debug code with Takashi's guideline.
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 84b9f9c..0233425 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -595,7 +595,7 @@ int snd_usb_mixer_add_control(struct
usb_mixer_elem_list *list,
while (snd_ctl_find_id(mixer->chip->card, &kctl->id))
kctl->id.index++;
if ((err = snd_ctl_add(mixer->chip->card, kctl)) < 0) {
- usb_audio_dbg(mixer->chip, "cannot add control (err = %d)\n",
+ usb_audio_err(mixer->chip, "[DEBUG] cannot add control
(err = %d)\n",
err);
return err;
}
@@ -2162,14 +2162,23 @@ static int parse_audio_selector_unit(struct
mixer_build *state, int unitid,
nameid = uac_selector_unit_iSelector(desc);
len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
+
+ usb_audio_err(state->chip, "[DEBUG] nameid:%d, len:%d\n", nameid, len);
+
if (len)
;
- else if (nameid)
+ else if (nameid) {
len = snd_usb_copy_string_desc(state, nameid, kctl->id.name,
sizeof(kctl->id.name));
- else
+ usb_audio_err(state->chip, "[DEBUG] len:%d,
copy_string id.name:%s\n",
+ len, (len > 0) ? kctl->id.name : " ");
+ }
+ else {
len = get_term_name(state, &state->oterm,
kctl->id.name, sizeof(kctl->id.name), 0);
+ usb_audio_err(state->chip, "[DEBUG] len:%d, get_term_name:%s\n",
+ len, (len > 0) ? kctl->id.name : " ");
+ }
if (!len) {
strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
@@ -2182,7 +2191,7 @@ static int parse_audio_selector_unit(struct
mixer_build *state, int unitid,
append_ctl_name(kctl, " Playback Source");
}
- usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
+ usb_audio_err(state->chip, "[%d] SU [%s] items = %d\n",
cval->head.id, kctl->id.name, desc->bNrInPins);
return snd_usb_mixer_add_control(&cval->head, kctl);
}
2017-12-19 0:45 GMT+09:00 Takashi Iwai <tiwai@xxxxxxx>:
> On Mon, 18 Dec 2017 16:30:13 +0100,
> Mauro Santos wrote:
>>
>> On 18-12-2017 13:53, Takashi Iwai wrote:
>> > On Mon, 18 Dec 2017 14:44:44 +0100,
>> > Greg KH wrote:
>> >>
>> >> On Sun, Dec 17, 2017 at 06:56:05PM +0000, Mauro Santos wrote:
>> >>> I believe this is the right place to report this problem, but if it
>> >>> isn't please point me in the right direction.
>> >>
>> >> Adding the developer of that patch, and the sound maintainer and
>> >> developers to the thread.
>> >>
>> >>> I have noticed that after the update from kernel 4.14.5 to 4.14.6
>> >>> alsamixer does not show the usual volume controls for my usb soundcard.
>> >>>
>> >>> Reverting 3884d12e17ab770aa0f5d4bc65bfbfd006f417fa ALSA: usb-audio: Add
>> >>> check return value for usb_string() (from linux-stable) makes the
>> >>> controls come back again with kernel 4.14.6.
>> > (snip)
>> >>
>> >> This is odd, Takashi, I thought we fixed up the problem that if the
>> >> string was invalid, the code would continue to go on, it's not a "real"
>> >> error. Did that not get marked for the stable trees?
>> >
>> > Yes, it was marked as stable, and it's odd that the revert of the
>> > given commit changes the behavior in that way.
>> >
>> > Mauro, could you double-check whether reverting the commit really does
>> > fix it as expected? If yes, could you put some debug print at the
>> > part the patch touches, and check which unit id gives len=0 from
>> > snd_usb_copy_string_desc()?
>>
>> I'm sure reverting that patch makes things work as expected. I noticed
>> the problem after an update and that is the only thing I revert on top
>> of the kernel provided by the distro (Arch Linux).
>
> Did you revert only one patch, not both patches?
> Just to be sure.
>
>> Alsamixer works fine for the built in soundcard in my laptop, but the
>> mixer for the usb soundcard was not working so it's specific to usb and
>> only 2 patches touch the mixer.c file between 4.14.5 and 4.14.6. I've
>> tried reversing both, one at a time, and only reverting this one
>> restored the expected behavior.
>>
>> Regarding adding the debug print I'm going to need guidance. Without
>> reverting anything, would adding at line 2178 of sound/usb/mixer.c the
>> following be enough?
>>
>> printk("usbmixdbg: nameid=%d len=%d id.name=%s\n",nameid,len,kctl->id.name);
>>
>> It would then look like this (minus the line wrapping):
>> len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
>> printk("usbmixdbg: nameid=%d len=%d id.name=%s\n",nameid,len,kctl->id.name);
>> if (len)
>
> Well, at that point, there should be no difference.
> The difference is after that, so what I'd like to see is something
> like:
>
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -2175,14 +2175,18 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
>
> nameid = uac_selector_unit_iSelector(desc);
> len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
> + pr_info("XXX id=%d, check_mapped_name=%d\n", id, len);
> if (len)
> ;
> - else if (nameid)
> + else if (nameid) {
> len = snd_usb_copy_string_desc(state, nameid, kctl->id.name,
> sizeof(kctl->id.name));
> - else
> + pr_info("XXX id=%d, copy_string=%d\n", len);
> + } else {
> len = get_term_name(state, &state->oterm,
> kctl->id.name, sizeof(kctl->id.name), 0);
> + pr_info("XXX id=%d, get_term_name=%d\n", len);
> + }
>
> if (!len) {
> strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
>
>
> If you see copy_string=0, it means that your hardware reports a bogus
> entry, and the driver does it correctly. If ignoring that error
> really restores the old behavior back, it essentially means that it
> worked casually in the past...
AudioControl Interface Descriptor:
bLength 8
bDescriptorType 36
bDescriptorSubtype 5 (SELECTOR_UNIT)
bUnitID 11
bNrInPins 2
baSource( 0) 14
baSource( 1) 5
iSelector 0
^^^^^^^^^
>From the lsusb.txt, iSelector is '0' which means
uac_selector_unit_iSelector() return zero I think.
Thanks, jaejoong
>
>
> thanks,
>
> Takashi
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 84b9f9c..0233425 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -595,7 +595,7 @@ int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
while (snd_ctl_find_id(mixer->chip->card, &kctl->id))
kctl->id.index++;
if ((err = snd_ctl_add(mixer->chip->card, kctl)) < 0) {
- usb_audio_dbg(mixer->chip, "cannot add control (err = %d)\n",
+ usb_audio_err(mixer->chip, "[DEBUG] cannot add control (err = %d)\n",
err);
return err;
}
@@ -2162,14 +2162,23 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
nameid = uac_selector_unit_iSelector(desc);
len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
+
+ usb_audio_err(state->chip, "[DEBUG] nameid:%d, len:%d\n", nameid, len);
+
if (len)
;
- else if (nameid)
+ else if (nameid) {
len = snd_usb_copy_string_desc(state, nameid, kctl->id.name,
sizeof(kctl->id.name));
- else
+ usb_audio_err(state->chip, "[DEBUG] len:%d, copy_string id.name:%s\n",
+ len, (len > 0) ? kctl->id.name : " ");
+ }
+ else {
len = get_term_name(state, &state->oterm,
kctl->id.name, sizeof(kctl->id.name), 0);
+ usb_audio_err(state->chip, "[DEBUG] len:%d, get_term_name:%s\n",
+ len, (len > 0) ? kctl->id.name : " ");
+ }
if (!len) {
strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
@@ -2182,7 +2191,7 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
append_ctl_name(kctl, " Playback Source");
}
- usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
+ usb_audio_err(state->chip, "[%d] SU [%s] items = %d\n",
cval->head.id, kctl->id.name, desc->bNrInPins);
return snd_usb_mixer_add_control(&cval->head, kctl);
}
