[alsa-devel] [PATCH v2] Scarlett mixer interface inclusion

[Takashi Iwai]

At Tue, 21 Oct 2014 14:46:26 -0500,
Chris J Arges wrote:
> 
> This is a followup to David Henningsson's PATCH [1] to include the work of
> Tobias Hoffman and Robin Gareus in getting the Scarlett mixer interface
> working. I've read through the comments and tried to include fixes where
> appropriate. 
> 
> Overall, I'd like to get a good base commit and start working on other commits
> that address any major structual changes such as making functions more generic
> or any other cleanup.

Use 3.18-rc1 as the baseline.

> I've tested this on my Scarlett 18i8 mixer and it does work, however there
> are still a few issues which need to be fixed:
> 
> 1) When loading a device one gets the following messages:
> snd-usb-audio 1-1.1:1.0: control 2:0:0:Master Playback Switch:0 is already present
> snd-usb-audio: probe of 1-1.1:1.3 failed with error -5

This is certainly a driver problem, as the message says.

> 2) When unloading a device there are numerous sysfs_remove_group issues:
> usb 1-1.1: USB disconnect, device number 6
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 54 at /build/buildd/linux-3.16.0/fs/sysfs/group.c:219 sysfs_remove_group+0x99/0xa0()
> sysfs group ffffffff82cbd6e0 not found for kobject 'midi1'
(snip)
> However this issue occured even without the patch applied.

Yes, there was a similar report, but we couldn't reproduce here.
It's a Oops coming from OSS midi device.  This is fairly harmless, but
annoying.  Could you give your kernel config?  Maybe there's some
difference.


Takashi