Bug#704305: not working reliably with USB devices

[Daniel Pocock]

On 14/04/14 06:29, Felipe Sateler wrote:
> Control: tag -1 moreinfo
> 
> Hi Daniel,
> 
>> The device works fine on another system, a server with a pulseaudio
>> daemon process set up manually.  On the default desktop gnome setup,
>> however, I'm finding pulseaudio highly unreliable with a USB device,
>> Creative Soundblaster X-Fi HD.  Other people report similar problems.
> 
> I'm not sure what you mean by unreliable. Do you still see problems
> with pulseaudio 5.0 from unstable?
> 

I've merged in #756860 (X-fi USB not working on ARM) as the symptoms
look exactly like those on my Intel-based laptop in this bug #704305

Just upgraded the laptop to jessie and the problems are still there
using this device.

I managed to make it more reliable by modifying /etc/pulse/default.pa
and putting these lines near the top:


    load-module module-alsa-sink device=hw:1,2

    load-module module-alsa-card device_id=1


and adding tsched=0 to this line:

    load-module module-udev-detect tsched=0

A patch is attached showing exactly what I did.

That is not the whole story though.  Each time I reconnect it to the USB
port, I have to kill pulseaudio with:

      $ pulseaudio -k

Each time I start playing something, I have to run

      $ pavucontrol

and go to the stream that is playing and change the output device from
whatever it is on to "USB Sound Blaster HD".

When it does work, it works indefinitely and reliably until the machine
is stopped or the USB unplugged.

After making these changes to default.pa, pavucontrol will often show it
as more than one device, I'll usually see both of these:

   USB Sound Blaster HD
   USB Sound Blaster HD Analog Stereo

This laptop has built-in sound hardware and it also has HDMI output
which supports digital sound.  I will usually see a wide range of
possible device configurations (e.g. IEC958 Output + Analog Input,
IEC958 Duplex, ...)

Looking through Google, many other things come up:

- some people reported crackling sounds, some suggest adding the
"tsched=0" parameter fixes that

- one suggested adding a file /etc/modprobe.d/alsa-base.conf with:

   options snd-hda-intel position_fix=1 model=3stack

- another suggested modifying /usr/share/alsa/cards/USB-Audio.conf and
adding the "USB Sound Blaster HD" like this:

--- USB-Audio.conf	2014-12-06 17:30:32.479462361 +0100
+++ USB-Audio.conf-X-Fi	2014-12-06 17:30:42.179462018 +0100
@@ -33,40 +33,41 @@
 }

 # If a device does not use the first PCM device for digital data, the
device
 # number for the iec958 device can be changed here.
 USB-Audio.pcm.iec958_device {
+
+	"USB Sound Blaster HD" 1

 	# "NoiseBlaster 3000" 42

 	# The below don't have digital in/out, so prevent them from being opened.
 	"Blue Snowball" 999
 	"HP Digital Stereo Headset" 999
 	"Logitech Speaker Lapdesk N700" 999
 	"Logitech USB Headset" 999
 	"Logitech Wireless Headset" 999
 	"Plantronics GameCom 780" 999
 	"Plantronics USB Headset" 999
 	"Plantronics Wireless Audio" 999
 	"SB WoW Headset" 999
 	"Scarlett 2i2 USB" 999
 	"Sennheiser USB headset" 999
 	"USB Device 0x46d:0x992" 999
 }




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