[ALSA - driver 0000425]: usb-usx2y: System lockup on PCM device open (OHCI)

[bugtrack@alsa-project.org]

A BUGNOTE has been added to this bug.
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https://bugtrack.alsa-project.org/alsa-bug/bug_view_page.php?bug_id=0000425
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Reported By:                rncbc
Assigned To:                karsten
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Project:                    ALSA - driver
Bug ID:                     425
Category:                   USB - usb-usx2y
Reproducibility:            always
Severity:                   block
Priority:                   normal
Status:                     assigned
Distribution:               Mandrake 10.0 Official
Kernel Version:             2.6.8-rc2
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Date Submitted:             08-06-2004 10:53 CEST
Last Modified:              09-25-2004 17:18 CEST
======================================================================
Summary:                    usb-usx2y: System lockup on PCM device open (OHCI)
Description: 
As of ALSA 1.0.6rc1, the US-x2y PCM device driver module exposes a hard
conflict on OHCI based USB controllers, causing a complete system lockup
-- kernel oops on an interrupt handler -- exactly upon starting or
openning the PCM device for audio playback. 
======================================================================

----------------------------------------------------------------------
 rncbc - 08-06-2004 12:16 CEST 
----------------------------------------------------------------------
Just to add, that this issue does not occur as of previous
alsa-driver-1.0.5a, same platform, kernel or hardware. Seems to have been
introduced on CVS semewhere since mid-July. Something about "no sleeping"
in ALSA's pcm START/STOP callbacks, but no sure.

----------------------------------------------------------------------
 karsten - 09-23-2004 20:52 CEST 
----------------------------------------------------------------------
that seams to have something to do with a threaded IRQ10?
Does it also happen with hardirq_preempting off?
Please geneate oops traces from the 2.6.9-rc2-mmx-Sy kernel also. 
If those traces also happen in non usx2y-module area,
find out, which snd_*() call triggers the oops.
Check wether it happens if you disable hyperthreads.
Erm, did I fail to include some important errorchecks after calling
kernel/usb functions?
Run with at least ALSA debug options enabled. Other kernel debug options
may help too.

----------------------------------------------------------------------
 rncbc - 09-24-2004 09:43 CEST 
----------------------------------------------------------------------
Please note that this problem is not related to the voluntary-preempt
kernel patch nor is SMP/HT related. The machine where its beeing exposed
is a Compaq Presario 2516EA (laptop), P4 2.533GHz (UP, no-HT enabled).

Also FWIW, it doesn't matter if ACPI is enabled or not. The point where
the kernel oops occurs seems to be always under ohci_hcd (see
hard-screenshot).

----------------------------------------------------------------------
 rncbc - 09-25-2004 17:18 CEST 
----------------------------------------------------------------------
Now using 2.6.9-rc2-mm3-S6 (voluntary-preempt).

One thing I've noticed, but just related to VP, is that while having
hardirq-preempt=1 and /proc/irq/10/ohci_hcd/threaded=1, the kernel
doesn't
crash when opening the PCM hw device (either via jackd or aplay). But
still useless or zombie anyway. It does crash however when I unplug my
US-224 (switch its power down).

With hardirq-preempt=0 or /proc/irq/10/ohci_hcd/threaded=0, I get the
same
old bad behavior: a kernel oops somewhere on the ohci_irq handling,
almost
immediately when the PCM device is open (e.g. by jackd or aplay). Yet
another screenshot added here (usx2y-oops4.png).

Bug History
Date Modified  Username       Field                    Change              
======================================================================
08-06-04 10:53 rncbc          New Bug                                      
08-06-04 10:53 rncbc          File Added: usx2y-oops3.png                    
08-06-04 10:53 rncbc          Distribution              => Mandrake 10.0 Official
08-06-04 10:53 rncbc          Kernel Version            => 2.6.8-rc2       
08-06-04 12:16 rncbc          Bugnote Added: 0001538                       
09-23-04 20:52 karsten        Bugnote Added: 0001849                       
09-24-04 09:43 rncbc          Bugnote Added: 0001858                       
09-25-04 17:13 rncbc          File Added: usx2y-oops4.png                    
09-25-04 17:18 rncbc          Bugnote Added: 0001911                       
======================================================================


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