[LAD] More on alsa card order and udev

Slow day at work so I've been doing some testing. I'm using Fedora 11 preview on my spare R&D PC. I've got a Behringer UMA25S which is a 25 key MIDI keyboard with built in USB soundcard. I haven't removed anything from F11 so pulseaudio et al is still installed. Problem 1 F11 no longer loads snd_seq (oss support which loads snd_seq conflicts with PA). I just manually modprobe'd snd_seq pending a proper fix. Action 1 Plug everything in. Run the following command for each device in /dev/snd udevadm info -a -p $(udevadm info -q path -n /dev/snd/DEVICE_NAME) and save the outputs. You can use these to determine how to specify an individual device/card in the udev rules. Action 2 I added the following lines to /etc/udev/rules/90-alsa.rules (each line starts with either # (for a comment) or KERNEL so if your mail reader breaks them up, join them back together. You will need different tests to identify your individual cards using the information gathered above :- # Make HDA Intel Card0 always KERNEL=="controlC*", SUBSYSTEM=="sound", DRIVERS=="HDA Intel", NAME="snd/controlC0" KERNEL=="hw*", SUBSYSTEM=="sound", ATTR{name}=="Realtek ALC880", NAME="snd/hwC0D2" KERNEL=="pcmC*c", SUBSYSTEM=="sound", DRIVERS=="HDA Intel", NAME="snd/pcmC0D0c" KERNEL=="pcmC*p", SUBSYSTEM=="sound", DRIVERS=="HDA Intel", NAME="snd/pcmC0D0p" # Make UMA25S Midi Card3 KERNEL=="midi*", SUBSYSTEM=="sound", ATTRS{product}=="UMA25S", ATTRS{manufacturer}=="BEHRINGER", NAME="snd/midiC3D0" KERNEL=="controlC*", SUBSYSTEM=="sound", ATTRS{product}=="UMA25S", ATTRS{manufacturer}=="BEHRINGER", NAME="snd/controlC3" # Make UMA25S Sound Card1 if in left front USB port KERNEL=="controlC*", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}=="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/controlC1" KERNEL=="pcmC*c", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}=="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC1D0c" KERNEL=="pcmC*p", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}=="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC1D0p" # Make UMA25S Sound Card2 if NOT in left front USB port # On a different USB bus KERNEL=="controlC*", SUBSYSTEM=="sound", ATTRS{busnum}!="2", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/controlC2" KERNEL=="pcmC*c", SUBSYSTEM=="sound", ATTRS{busnum}!="2", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC2D0c" KERNEL=="pcmC*p", SUBSYSTEM=="sound", ATTRS{busnum}!="2", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC2D0p" # Same USB bus, Different port KERNEL=="controlC*", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}!="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/controlC2" KERNEL=="pcmC*c", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}! ="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC2D0c" KERNEL=="pcmC*p", SUBSYSTEM=="sound", ATTRS{busnum}=="2", ATTRS{devnum}! ="5", ATTRS{product}=="USB Audio CODEC*", ATTRS{manufacturer}=="Burr-Brown from TI*", NAME="snd/pcmC2D0p" Action 3 Reboot and test it all. I started qjackctl and the USB soundcard showed up fine as card 1. I fired up a whysynth and connected the keyboard through jack - sound worked fine. Then I stopped jack, unplugged the UMA25 and tried a different USB port - even better, it now showed up as card2 in qjackctl and still worked once I told qjackctl to use card2 now. Problem 2 Move the card back to the original USB port and try again. It still shows as card2 ! A little investigation (lsusb) showed that although the card was back in the same place, it no longer had devnum==5. Each time you unplug and replug the device, even into the same physical socket, it gets a new devnum. This means that the usb devnum is not a reliable way of uniquely identifying a usb soundcard. Problem 3 /proc/asound/cards etc no longer correctly reflect the card numbers/names. This doesn't seem to affect Jack but I'm not sure where to start tracking this down to fix it. Perhaps someone with a bit more knowledge could take a look at this. Conclusion All told, a bit of a mixed bag of results but hopefully this may help someone to start a little further investigation and maybe we can make the udev/alsa combination do what is needed. Cheers, Simon