Re: [PATCH] work on usb_submit_urb returning -22 and "bad: scheduling while atomic!"

[Takashi Iwai <tiwai@suse.de>]

At Sat, 12 Jul 2003 23:45:08 -0500 (CDT),
Stephane Alnet wrote:
> 
> I hit two different problems; the first one has already been mentioned on
> the list a couple days ago and shows up as:
> 
> ALSA sound/usb/usbaudio.c:685: cannot submit datapipe for urb 0, err = -22
> (-22 is -EINVAL)
> 
> After some parsing of usb_submit_urb, I added some debugs in usbaudio.c
> and found out that urb->interval was set to 0, an invalid value. So I
> forced it to 1 and things started to work. (Obviously the proper fix may
> be to find why it's not properly initialized in the first place.)
 
yeah, that's a known problem of usb-audio driver on the recent 2.5/2.6
kernel...

> However I still had the "bad: scheduling while atomic!" problem I reported
> earlier on the list; sometimes I'd also get "Debug: sleeping function
> called from illegal context at kernel/sched.c:1489".

these errors should have been fixed on 0.9.5.
usb_submit_urb() was called in prepare callback of ALSA, which is
supposed to be atomic.

> Looking at the output
> from my debugs I saw that in some cases we were calling usb_submit_urb
> with a non-NULL urb->hcpriv, which isn't valid either.

hmm, this looks bad.

> So, I'm not sure what the root cause for this last problem is (besides the
> fact that schedule() is called within schedule()), but I kind of worked
> around it by guarding all the usb_submit_urb calls with a check for a NULL
> urb->hcpriv. I still get the same oopses when opening the device, and
> sound quality gets down under load (lost packets), but otherwise things
> seem to be working much better.
> 
> Attached are the diffs I made; it's getting late here so I'll check back
> on it tomorrow, but hopefully that'll give somebody some ideas of what I
> did. :-]

thanks for the patch.

i was working on this yesterday, 2.6.0-test1 was succesfully built,
and...  this morning i found my harddisk crashed completely :-<

too bad.


i still have only a 2.4 environment, so fixing this problem might take
a bit longer time.  please be patient.


Takashi


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