| Message ID | 20190821100225.9254-1-srinivas.kandagatla@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | ALSA: usb-audio: Fix the mixer control range limiting issue | expand |
On Wed, 21 Aug 2019 12:02:25 +0200, Srinivas Kandagatla wrote: > > From: Deepa Madiregama <dmadireg@codeaurora.org> > > - mixer_ctl_set() function is limiting the volume level > to particular range. This results in incorrect initial > volume setting for that device. > - In USB mixer while calculating the dBmin/dBmax values > resolution factor is hardcoded to 256 which results in > populating the wrong values for dBmin/dBmax. > - Fix is to use appropriate resolution factor while > calculating the dBmin/dBmax values. This change doesn't sound right. Basically the values returned from USB-audio FEATURE UNIT or MIXER UNIT are always in 1/256 dB unit, per definition. And we pass dB min/max to user-space as TLV_DB_MINMAX(), i.e. TLV points just both min and max, no matter what scale is. I believe that the current code is correct in this regard. So, it's either a firmware bug that gives the wrong values back, or the case we still don't cover, e.g. multiple RANGE values for UAC2/UAC3. Please check what exactly doesn't work as expected. Which value is returned from the USB-audio device and what is wrongly interpreted. thanks, Takashi > Signed-off-by: Deepa Madiregama <dmadireg@codeaurora.org> > Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org> > Signed-off-by: Meng Wang <mwang@codeaurora.org> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > --- > sound/usb/mixer.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c > index 5070a6a76ab3..a67448327d07 100644 > --- a/sound/usb/mixer.c > +++ b/sound/usb/mixer.c > @@ -1248,8 +1248,10 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval, > /* USB descriptions contain the dB scale in 1/256 dB unit > * while ALSA TLV contains in 1/100 dB unit > */ > - cval->dBmin = (convert_signed_value(cval, cval->min) * 100) / 256; > - cval->dBmax = (convert_signed_value(cval, cval->max) * 100) / 256; > + cval->dBmin = > + (convert_signed_value(cval, cval->min) * 100) / (cval->res); > + cval->dBmax = > + (convert_signed_value(cval, cval->max) * 100) / (cval->res); > if (cval->dBmin > cval->dBmax) { > /* something is wrong; assume it's either from/to 0dB */ > if (cval->dBmin < 0) > -- > 2.21.0 >
On 21/08/2019 18:05, Takashi Iwai wrote: > On Wed, 21 Aug 2019 12:02:25 +0200, > Srinivas Kandagatla wrote: >> >> From: Deepa Madiregama <dmadireg@codeaurora.org> >> >> - mixer_ctl_set() function is limiting the volume level >> to particular range. This results in incorrect initial >> volume setting for that device. >> - In USB mixer while calculating the dBmin/dBmax values >> resolution factor is hardcoded to 256 which results in >> populating the wrong values for dBmin/dBmax. >> - Fix is to use appropriate resolution factor while >> calculating the dBmin/dBmax values. > > This change doesn't sound right. Basically the values returned from > USB-audio FEATURE UNIT or MIXER UNIT are always in 1/256 dB unit, per > definition. And we pass dB min/max to user-space as TLV_DB_MINMAX(), > i.e. TLV points just both min and max, no matter what scale is. I > believe that the current code is correct in this regard. > > So, it's either a firmware bug that gives the wrong values back, or > the case we still don't cover, e.g. multiple RANGE values for > UAC2/UAC3. > > Please check what exactly doesn't work as expected. Which value is > returned from the USB-audio device and what is wrongly interpreted. > Thanks for the detailed review. I see https://www.usb.org/sites/default/files/audio10.pdf clearly specifies Mixer unit is always 1/256dB units. This patch has been carried in Qcom downstream kernels for past many years to fix very low Initial volume setting on some USB headsets like Logitech S-150 USB Speakers and Nokia HS-82 USB headset. Its highly likely that its a firmware bug!, but I will try to get it retested on latest kernel and collect some logs! Thanks, srini > > thanks, > > Takashi > > >> Signed-off-by: Deepa Madiregama <dmadireg@codeaurora.org> >> Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org> >> Signed-off-by: Meng Wang <mwang@codeaurora.org> >> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >> --- >> sound/usb/mixer.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c >> index 5070a6a76ab3..a67448327d07 100644 >> --- a/sound/usb/mixer.c >> +++ b/sound/usb/mixer.c >> @@ -1248,8 +1248,10 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval, >> /* USB descriptions contain the dB scale in 1/256 dB unit >> * while ALSA TLV contains in 1/100 dB unit >> */ >> - cval->dBmin = (convert_signed_value(cval, cval->min) * 100) / 256; >> - cval->dBmax = (convert_signed_value(cval, cval->max) * 100) / 256; >> + cval->dBmin = >> + (convert_signed_value(cval, cval->min) * 100) / (cval->res); >> + cval->dBmax = >> + (convert_signed_value(cval, cval->max) * 100) / (cval->res); >> if (cval->dBmin > cval->dBmax) { >> /* something is wrong; assume it's either from/to 0dB */ >> if (cval->dBmin < 0) >> -- >> 2.21.0 >>
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 5070a6a76ab3..a67448327d07 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1248,8 +1248,10 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval, /* USB descriptions contain the dB scale in 1/256 dB unit * while ALSA TLV contains in 1/100 dB unit */ - cval->dBmin = (convert_signed_value(cval, cval->min) * 100) / 256; - cval->dBmax = (convert_signed_value(cval, cval->max) * 100) / 256; + cval->dBmin = + (convert_signed_value(cval, cval->min) * 100) / (cval->res); + cval->dBmax = + (convert_signed_value(cval, cval->max) * 100) / (cval->res); if (cval->dBmin > cval->dBmax) { /* something is wrong; assume it's either from/to 0dB */ if (cval->dBmin < 0)