Bug 7303

Created attachment 9204 [details]
dmesg after docking

I just want to make clear how to duplicate the problem.
1.  Boot laptop docked.
2.  Undock
3.  Dock

Or is it:
1.  Boot laptop undocked
2.  Dock

?

Sorry for being somewhat unclear on my first report.

It's the first variant:
1.  Boot laptop docked.
2.  Undock
3.  Dock

If you like, i can test even the second variant. But earliest in three days, as
the dock is in my office and I'm at home the next two days.

I can even reproduce the bug with the second scenario.

1. Boot laptop undocked.
2. Dock laptop.

I'll attach a scecond dmesg.

Created attachment 9247 [details]
dmesg after docking a undocked laptop

I add some ugly debug printk's to dock.c, to get a better overview where this
bug triggers.

The bug occurs inside hotplug_dock_devices(), between debug STEP 13 and 14.

printk(KERN_INFO PREFIX "STEP 13\n");

    /*
     * Now make sure that an acpi_device is created for each
     * dependent device, or removed if this is an eject request.
     * This will cause acpi_drivers to be stopped/started if they
     * exist
     */
    list_for_each_entry(dd, &ds->dependent_devices, list) {
        printk(KERN_INFO PREFIX "STEP 14\n");

I have now idea about list_for_each_entry(). Hopefully this helps you to debug it.

I attach a dmesg and the modified dock.c for reference.

BTW, were you able to reproduce the bug?

Created attachment 9283 [details]
dmesg with debug.

Created attachment 9284 [details]
dock.c with debug.

Hi Stefan, 
Thanks for the additional debug output.  I have not had a chance to duplicate
the bug yet - I anticipate being able to spend time on this in a couple days. 
Thanks for your patience.

Kristen

Hi Stefan, I was not able to reproduce - can you attach your .config please,
there is probably something I don't have quite the same.

Thanks,
kristen

Created attachment 9311 [details]
.config

JFYI, I was able to reproduce this even with 2.6.19-rc2

regards
Stefan Schmidt

I was finally able to duplicate the problem - it seems to only happen while in
preempt mode.  I will try to find out if this is a generic problem with acpi, or
specific to something that I'm doing wrong.

Good to know. I began to think this is a local problem. ;)

Let me know if you have patches I should test.

Created attachment 9365 [details]
patch to switch from spinlock to mutex when hotplugging devices

Can you try out the patch I attached and see if it solves your problem?
thanks,
Kristen

I will test your patch at the beginning of the next week, as I have the docking
station in my office.

regards
Stefan Schmidt

I tested it now. The origin prblem seems fixed. No bug message in dmesg anymore.

But I got another message in dmesg now. Not sure yet if this comes rom the patch:

ACPI: docking
IPv6 addrconf: prefix with wrong length 56
IPv6 addrconf: prefix with wrong length 56
ACPI Exception (pci_bind-0302): AE_NOT_FOUND, Unable to get data from device
DOCK [20060707]
ACPI: undocking

The message :
ACPI Exception (pci_bind-0302): AE_NOT_FOUND, Unable to get data from device

Is ok and is expected when you are hot plugging (i.e. docking) a device
that previously had not existed.  so, this seems to be working as far as I can tell.

I'll submit this fix.

Ah, ok. The message was a bit confusing, as it talks about exeception.

I just saw your patch submit on lkml. Thanks for your work. I'm fine with it, so
you can close the bug.

regards
Stefan Schmidt

patch from comment #15 applied to acpi-test

shipped in 2.6.20-rc2
closed.