Re: Dell USB audio driver workaround

[Takashi Iwai <tiwai@suse.de>]

On Tue, 12 Apr 2016 05:02:08 +0200,
Kailang wrote:
> 
> 
> Hi Takashi,
> 
> Attach is new patch witch follow your method.
> Many Thanks for you. ^^

OK, I applied it with a few modification / correction in the comments
and the changelog.  Also added Cc to stable.


thanks,

Takashi


> 
> BR,
> Kailang 
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de] 
> > Sent: Thursday, April 07, 2016 6:18 PM
> > To: Kailang
> > Cc: (alsa-devel@alsa-project.org)
> > Subject: Re: Dell USB audio driver workaround
> > 
> > On Thu, 07 Apr 2016 12:07:25 +0200,
> > Kailang wrote:
> > > 
> > >  
> > > 
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > Sent: Thursday, April 07, 2016 5:27 PM
> > > > To: Kailang
> > > > Cc: (alsa-devel@alsa-project.org)
> > > > Subject: Re: Dell USB audio driver workaround
> > > > 
> > > > On Thu, 07 Apr 2016 09:05:52 +0200,
> > > > Kailang wrote:
> > > > > 
> > > > >  
> > > > > 
> > > > > > -----Original Message-----
> > > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > > Sent: Wednesday, April 06, 2016 5:37 PM
> > > > > > To: Kailang
> > > > > > Cc: (alsa-devel@alsa-project.org)
> > > > > > Subject: Re: Dell USB audio driver workaround
> > > > > > 
> > > > > > On Wed, 06 Apr 2016 11:22:43 +0200, Kailang wrote:
> > > > > > > 
> > > > > > >  
> > > > > > > 
> > > > > > > > -----Original Message-----
> > > > > > > > From: Takashi Iwai [mailto:tiwai@suse.de]
> > > > > > > > Sent: Wednesday, April 06, 2016 4:57 PM
> > > > > > > > To: Kailang
> > > > > > > > Cc: (alsa-devel@alsa-project.org)
> > > > > > > > Subject: Re: Dell USB audio driver workaround
> > > > > > > > 
> > > > > > > > On Wed, 06 Apr 2016 08:29:12 +0200, Kailang wrote:
> > > > > > > > > 
> > > > > > > > > Hi Takashi,
> > > > > > > > > 
> > > > > > > > > Dell had USB dock.
> > > > > > > > > Maybe firmware issue, the master volume always 
> > keep at 0x57.
> > > > > > > > > Attach patch will fix it to keep at Max volume.
> > > > > > > > > 
> > > > > > > > > Could you help us to update it?
> > > > > > > > 
> > > > > > > > Well, I don't get how this patch works..
> > > > > > > > 
> > > > > > > > > diff --git a/sound/usb/mixer.c 
> > b/sound/usb/mixer.c index 
> > > > > > > > > 4f85757..84d9a4e 100644
> > > > > > > > > --- a/sound/usb/mixer.c
> > > > > > > > > +++ b/sound/usb/mixer.c
> > > > > > > > > @@ -846,6 +846,12 @@ static void
> > > > volume_control_quirks(struct
> > > > > > > > > usb_mixer_elem_info *cval,  {
> > > > > > > > >  	struct snd_usb_audio *chip = 
> > cval->head.mixer->chip;
> > > > > > > > >  	switch (chip->usb_id) {
> > > > > > > > > +	case USB_ID(0x0bda, 0x4014): /* Dell 
> > workaround */
> > > > > > > > > +		if (strstr(kctl->id.name, "Playback
> > > > > > Volume") != NULL) {
> > > > > > > > > +			cval->min = 0x0000;
> > > > > > > > > +			cval->max = 0x0000;
> > > > > > > > > +		}
> > > > > > > > > +		break;
> > > > > > > > 
> > > > > > > > So, this means that this value has to be fixed to 0?
> > > > > > > > If yes, can't we simply remove this volume instead?
> > > > > > > 
> > > > > > > Yes, but it need to set Max volume to 0. This is test
> > > > on my site.
> > > > > > > Because it will rewrite 0x57 value to codec register when
> > > > > > driver is loaded.
> > > > > > > And keep 0x57 volume value all the time. So, Master volume
> > > > > > will lower than windows machine.
> > > > > > > This case which driver fail to build the alsa mixer(This is
> > > > > > firmware cause it). So, no hardware volume control on this.
> > > > > > > If the Max volume value is 0,  system will not set default
> > > > > > value 0x57 for first time loading driver.
> > > > > > 
> > > > > > Which values (min/max) does this FU take and which values
> > > > are buggy?
> > > > > Max value. 
> > > > 
> > > > Sorry, my question wasn't clear.  "What" min and max are they?  
> > > > min=0 and max=0x57?
> > > 
> > > Oh! Sorry. It's my wrong. I forgot.
> > > 
> > > Unit: 16
> > >     Control: name="PCM Playback Volume", index=0
> > >     Info: id=16, control=2, cmask=0x3, channels=2, type="S16"
> > >     Volume: min=-16256, max=0, dBmin=-6350, dBmax=0
> > > 
> > > 0x0 (codec reg)  = (-16256) (USB vloume level) 0x57(codec reg) = 
> > > 0xEC00(USB vloume level) 0x7F(codec reg) = 0x0000 (USB vloume level)
> > > 
> > > > 
> > > > And, your patch changes both min and max to be 0.  That is, it 
> > > > accepts only 0.  Does it mean that this FU isn't any 
> > proper volume 
> > > > control?
> > > 
> > > cval->max original is 0.
> > > cval->min => I set it to 0. It will be not rewrite 0x57 
> > value to codec.
> > 
> > OK, now it's clear, thanks.
> > 
> > Though, I still don't like to set min = max.  It basically 
> > makes this control useless, and then there is no reason to 
> > keep this exposed.
> > 
> > Can we just skip parsing this control, then?  You can create 
> > an own usbmix_name_map[] to indicate the ID to skip building 
> > a control by passing NULL to its name.  That is, a patch like 
> > below.  (You need to fill the right ID number in the patch, 
> > of course.)
> > 
> > 
> > Takashi
> > 
> > ---
> > diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
> > --- a/sound/usb/mixer_maps.c
> > +++ b/sound/usb/mixer_maps.c
> > @@ -349,6 +349,16 @@ static struct usbmix_name_map 
> > bose_companion5_map[] = {  };
> >  
> >  /*
> > + * Dell XXX with ALC4020 codec had a firmware problem where it got
> > + * screwed up when zero volume is passed; just skip it as a 
> > workaround  
> > +*/ static const struct usbmix_name_map dell_alc4020_map[] = {
> > +	{ 10 /* XXX fill this right ID XXX */, NULL },
> > +	{ 0 }
> > +};
> > +
> > +
> > +/*
> >   * Control map entries
> >   */
> >  
> > @@ -423,6 +433,10 @@ static struct usbmix_ctl_map 
> > usbmix_ctl_maps[] = {
> >  		.map = maya44_map,
> >  	},
> >  	{
> > +		.id = USB_ID(0x0bda, 0x4014),
> > +		.map = dell_alc4020_map,
> > +	},
> > +	{
> >  		.id = USB_ID(0x0c45, 0x1158),
> >  		.map = justlink_map,
> >  	},
> > 
> > ------Please consider the environment before printing this e-mail.
> > 
> [2 0001-Dell-usb-dock-vloume-issue.patch <application/octet-stream (base64)>]
>