Ubuntu
linux-signed-hwe package

Ubuntu Studio, cannot modprobe snd-usb-audio on linux-5.0.0-29-lowlatency

Asked by Jerker Gustafsson

Hi,

I tried to update the pcm.c file in linux-5.0.0/sound/usb/ with the following patch at line 357:
<->
 case USB_ID(0x0582, 0x01d8): /* Boss Katana 100 */
   return 0;
<->
My kernel is: 5.0.0-29-lowlatency

I followed this procedure:
585 sudo apt install build-essential -y
  586 sudo apt build-dep linux -y
  587 sudo apt build-dep linux
  588 mkdir katana
  589 cd katana/
  590 apt source linux
  591 ls
  592 cd linux-5.0.0/
  593 ls
  594 cp /lib/modules/`uname -r`/build/.config . -v
  595 cp /lib/modules/`uname -r`/build/Module.symvers . -v
  596 uname -r
  597 ls
  598 emacs Makefile &
  599 make modules_prepare
  600 lsusb | grep Roland
  601 make M=sound/usb
  602 sudo cp /lib/modules/`uname -r`/kernel/sound/usb/snd-usb-audio.ko /lib/modules/`uname -r`/kernel/sound/usb/snd-usb-audio.ko.old -v
  603 sudo rmmod snd-usb-audio
  604 sudo cp ./sound/usb/snd-usb-audio.ko /lib/modules/`uname -r`/kernel/sound/usb/snd-usb-audio.ko -v
  605 sudo depmod -a
  606 sudo modprobe snd-usb-audio

I noticed that the procedure above was developed for 5.0.0-16-lowlatency, is there a difference between 5.0.0-16-lowlatency and 5.0.0-29-lowlatency that requires a change in the procedure?

Is it so that the patch listed above is going to be included in the 5.0.0-xx-lowlatency kernel in the future?

looking forward to your answer
/Jerker

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Jerker Gustafsson
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Jerker Gustafsson (jerrymek) said : 		#1

And the gcc version is:

$ gcc --version
gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Revision history for this message
Manfred Hampl (m-hampl) said : 		#2

For diagnostic purposes please provide the output that you receive for the commands

uname -a
lsb_release -crid
sudo modprobe -v snd-usb-audio

Revision history for this message
Jerker Gustafsson (jerrymek) said : 		#3

uname -a
Linux Hummingbird-II 5.0.0-29-lowlatency #31-Ubuntu SMP PREEMPT Thu Sep 12 14:13:01 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 19.04
Release: 19.04
Codename: disco

sudo modprobe -v snd-usb-audio
modprobe: FATAL: Module snd-usb-audio not found in directory /lib/modules/5.0.0-29-lowlatency

Revision history for this message
Jerker Gustafsson (jerrymek) said : 		#4

And most importantly: thanks for looking into this.

Revision history for this message
Manfred Hampl (m-hampl) said : 		#5

What output do you receive for
find /lib/modules/ -name 'snd*usb*audio*' -ls

Revision history for this message
Jerker Gustafsson (jerrymek) said : 		#6

$ find /lib/modules/ -name 'snd*usb*audio*' -ls
  6162212 348 -rw-r--r-- 1 root root 356041 aug 20 21:25 /lib/modules/5.0.0-27-lowlatency/kernel/sound/usb/snd-usb-audio.ko
  8131268 348 -rw-r--r-- 1 root root 355416 sep 25 22:45 /lib/modules/5.0.0-29-lowlatency/kernel/sound/usb/snd-usb-audio.ko

Please note that the snd-usb-audio.ko in 5.0.0-29-lowlatency is the faulty one:
$ sudo modprobe snd-usb-audio
modprobe: ERROR: could not insert 'snd_usb_audio': Exec format error

My question is how can I get a correct snd-usb-audio.ko?

Revision history for this message
Jerker Gustafsson (jerrymek) said : 		#7

Problem solved, I reinstalled the kernel and gave the depmode and depmode commands.
Thanks for looking into my problem Manfred. Much appreciated.
brdgs
Jerker