Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Ivica Bukvic]

Hi all,

This is my latest finding. Thanks to the script I got from Jaroslav, I
am now able to hotplug my midisport 2x2 whenever I wish to do so.
However, there is an interesting problem surrounding Mdk9.0.

If I use the planet ccrma's hotplug ver. 2002_8_26 (by forcing upgrade
of the mdk's), I get the fxload and all the goodies making the midisport
work right out-of-the-box. However, with one huge flaw: 

When I unplug the midisport (after having the alsasound hotplug script
installed), my kernel oops and system freezes telling me something about
"disabling interrupt handler." (if someone tells me where I can track
this information log I will be happy to forward it). So, I am simply not
allowed to unplug the device.

In addition my /var/log/messages relatively often spits out the
following message:
<date> <host> kernel: usb-uhci.c: interrupt, status 3, frame#
<some_number>

I've tracked down the problem to the /sbin/modprobe -r snd-usb-midi (and
snd-usb-audio). If I move this thing somewhere else in the alsasound
hotplug script (like purging it at load-time and then reloading the
driver, rather than on disconnect) then the freeze occurs at that point.
When I comment it out, no freezes occur. So, I am pretty sure that is
the culprit.


On the other hand, if I downgrade to Mdk's hotplug ver. 2002_4_01, then
no oops occur (except one has to put alsasound.usermap and
ezusbmidi.usermap to /etc/hotplug/usb.usermap.local, since this older
version does not support usb sub-dir placing of usermaps. However in
this case my midisport offers me only 1 I/O device (even though it is
2x2), as opposed to the ccrma's which rightly gives me 2. (both report
locating 2 I and 2 o devices in /var/log/messages log, but only ccrma's
offers both devices via /dev/midi*).

I tried diff-ing the files from the two rpm packages to see if I am able
to locate the place where this dramatic change occurs, but found that
most of the files involved in the two packages are rather similar, if
not the same, major difference being the support of the usb/ subdir for
storing module scripts.

So, what gives?

Anyone has a clue? What is so different between the two packages that
one causes kernel oops/freeze, while the other one gives me only one i/o
midi port?

The files contained within each package are mostly files located in
/etc/hotplug dir, some man stuff, and fxload and hotplug from the /sbin/
dir (fxload being present in later hotplug package, while for the older
one, I extracted only that file from the ccrma's package and put it in
the right place).

In addition to this, I just noticed that the same message is showing up
in my /var/log/messages when using the mdk's package, so that one most
likely is not the problem, or at least not associated with this issue...

Any help is greatly appreciated! Sinceerely,

Cc: mdk bug reports


Ivica Ico Bukvic, composer, multimedia sculptor,
programmer, webmaster & computer consultant 
http://meowing.ccm.uc.edu/~ico 
============================ 
"To be or not to be" - Shakespeare
"To be is to do"     - Socrates
"To do is to be"     - Sartre
"Do be do be do"     - Sinatra
"2b || ! 2b"         - ?
"I am"               - God




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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Takashi Iwai]

At Thu, 27 Feb 2003 13:00:10 -0500,
Ivica Bukvic wrote:
> 
> Hi all,
> 
> This is my latest finding. Thanks to the script I got from Jaroslav, I
> am now able to hotplug my midisport 2x2 whenever I wish to do so.
> However, there is an interesting problem surrounding Mdk9.0.
> 
> If I use the planet ccrma's hotplug ver. 2002_8_26 (by forcing upgrade
> of the mdk's), I get the fxload and all the goodies making the midisport
> work right out-of-the-box. However, with one huge flaw: 
> 
> When I unplug the midisport (after having the alsasound hotplug script
> installed), my kernel oops and system freezes telling me something about
> "disabling interrupt handler." (if someone tells me where I can track
> this information log I will be happy to forward it). So, I am simply not
> allowed to unplug the device.
> 
> In addition my /var/log/messages relatively often spits out the
> following message:
> <date> <host> kernel: usb-uhci.c: interrupt, status 3, frame#
> <some_number>
> 
> I've tracked down the problem to the /sbin/modprobe -r snd-usb-midi (and
> snd-usb-audio). If I move this thing somewhere else in the alsasound
> hotplug script (like purging it at load-time and then reloading the
> driver, rather than on disconnect) then the freeze occurs at that point.
> When I comment it out, no freezes occur. So, I am pretty sure that is
> the culprit.

hmm, the hot unplugging of ALSA usb devices was improved in the recent
version - basically i didn't see problems with the devices i have.
but i've not tested with midi devices, so this might be a problem.

just make sure that you unload snd-usb-audio (snd-usb-midi doesn't
exist any longer) before unplugging the device.


Takashi


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RE: [Alsa-devel] Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Ivica Bukvic]

Actually, now that I have reinstalled the src.rpm package of hotplug
8_26_2002 (from sourceforge), I do get both the 2 midi ports and audio
(crashes still occur). I've now discovered two more interesting issues:

1) Upon booting and installing the midisport 2x2 for the first time
(regardless whether that is at boot time or afterwards), I get 2 midi
ports and everything is ok. If I then disconnect and reconnect it,
everything is still ok, but now I only have 1 midi port. Seems like only
the first time is a charm. This is no biggie, since I've overcome the
major problems, but still may point to some kind of a bug in (I presume)
Alsa.

2) The other rather important observation is that the crash (kernel
oops) occurs, when I omit the /sbin/modprobe -r snd-usb-midi line from
the Jaroslav's script as you have suggested (this has happened several
times and every time I comment it out, the thing crashes with the same
interrupt handler async oops, while the system remains rock solid
regardless of numbers of reconnects when the thing is not commented
out).

It makes me wonder whether that call to remove a module that does not
exist gives the kernel enough time to clean up something usb-related on
its side before invoking the removal of the module, therefore avoiding
the oops (the second line /sbin/modprobe -r snd-usb-audio). It would be
perhaps a good idea to do a small sleep command there and see whether
that would work as well as the above-mentioned removal of the
non-existent module (but I don't know how to put one there since I am
not that good with shell scripts -- any ideas are welcome though).

Still, the issue of reconnect giving you only 1 midi port remains. :-)

Note: mandrake-expert developers, if you need the script and config
e-mailed in order to have Mandrake 9.0 auto-detect alsasound devices and
dynamically load them, please contact me and I'll e-mail them to ya.

Ico




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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Patrick Shirkey]

Takashi Iwai wrote:

> 
> hmm, the hot unplugging of ALSA usb devices was improved in the recent
> version - basically i didn't see problems with the devices i have.
> but i've not tested with midi devices, so this might be a problem.
> 
> just make sure that you unload snd-usb-audio (snd-usb-midi doesn't
> exist any longer) before unplugging the device.
> 
> 


I see it too with the quattro and another user has reported it with the 
audigy. It would be nicer if we didn't have to remember to unload the 
usb-audio driver before hotplugging. Is it possible to make that happen.

-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman



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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Takashi Iwai]

At Fri, 28 Feb 2003 14:51:08 +0900,
Patrick Shirkey wrote:
> 
> Takashi Iwai wrote:
> 
> > 
> > hmm, the hot unplugging of ALSA usb devices was improved in the recent
> > version - basically i didn't see problems with the devices i have.
> > but i've not tested with midi devices, so this might be a problem.
> > 
> > just make sure that you unload snd-usb-audio (snd-usb-midi doesn't
> > exist any longer) before unplugging the device.
> > 
> > 
> 
> 
> I see it too with the quattro and another user has reported it with the 
> audigy. It would be nicer if we didn't have to remember to unload the 
> usb-audio driver before hotplugging. Is it possible to make that happen.

then there is still a bug in this regard.
are you using MIDI on quattro, too?


Takashi


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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Patrick Shirkey]

Takashi Iwai wrote:

>>
>>I see it too with the quattro and another user has reported it with the 
>>audigy. It would be nicer if we didn't have to remember to unload the 
>>usb-audio driver before hotplugging. Is it possible to make that happen.
> 
> 
> then there is still a bug in this regard.
> are you using MIDI on quattro, too?
> 

It is automatically used. Clemens would have to explain as I cannot 
remember the exact details.


-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman



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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Patrick Shirkey]

Patrick Shirkey wrote:
> Takashi Iwai wrote:
> 
>>>
>>> I see it too with the quattro and another user has reported it with 
>>> the audigy. It would be nicer if we didn't have to remember to unload 
>>> the usb-audio driver before hotplugging. Is it possible to make that 
>>> happen.
>>
>>
>>
>> then there is still a bug in this regard.
>> are you using MIDI on quattro, too?
>>
> 
> It is automatically used. Clemens would have to explain as I cannot 
> remember the exact details.
> 

I another bug I was just reminded of is that if I remove the alsa 
modules while the usb device is still switched on I get a complete hang 
where I have to restart with alt+sysreq+b


-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman



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Re: Interesting problem with hotplug and Midisport 2x2 on Mdk 9.0

[Clemens Ladisch]

Patrick Shirkey wrote:
> Patrick Shirkey wrote:
> > Takashi Iwai wrote:
> >>> I see it too with the quattro and another user has reported it with
> >>> the audigy. It would be nicer if we didn't have to remember to unload
> >>> the usb-audio driver before hotplugging. Is it possible to make that
> >>> happen.
> >>
> >> then there is still a bug in this regard.
> >> are you using MIDI on quattro, too?
> >
> > It is automatically used. Clemens would have to explain as I cannot
> > remember the exact details.

MIDI input always has a URB submitted.

> I another bug I was just reminded of is that if I remove the alsa
> modules while the usb device is still switched on I get a complete hang
> where I have to restart with alt+sysreq+b

All these crashes look like the bug which has been fixed on 13th January,
so it should work with 0.9.0rc7. Nothing like this happens with my devices
(UA-1A and SC-8820), and I regularly plug/unplug them and load/unload the
drivers during debugging.


HTH
Clemens




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