Greg KH wrote:
> On Thu, May 18, 2006 at 06:42:02PM -0400, Brian Walsh wrote:
>> Brian Walsh wrote:
>>> Brian Walsh wrote:
>>>> Greg KH wrote:
>>>>> On Wed, May 17, 2006 at 01:26:33PM -0400, Brian Walsh wrote:
>>>>>> I am having a problem with a cardbus modem. The cardbus device has an
>>>>>> internal
>>>>>> OHCI host controller and 2 usbserial devices attached to that
>>>>>> controller. I am
>>>>>> running a 2.6.16 kernel on an Arm ixp425 Coyote based system.
>>>>>>
>>>>>> The device works fine. However to insert the device I must first unload
>>>>>> the
>>>>>> ohci_hcd module. Insert the card and then let hotplug take care of
>>>>>> reinitializing everything. All the ohci host devices are reattached
>>>>>> along with
>>>>>> all the attached usb devices.
>>>>>>
>>>>>> If I insert the card without unloading the ohci_hcd module hotplug will
>>>>>> see and
>>>>>> attach the ohci host controller but never attaches the usbserial devices.
>>>>> Can you post the kernel log messages (with CONFIG_USB_DEBUG enabled) for
>>>>> when you do this?
>>>>>
>>>>> Oh, and does this work properly on a i386 machine?
>>>>>
>>>> I posted the log files. They were a bit long to post to the list.
>>>>
>>>> http://www.walsh.ws/usb_hang.txt
>>>> http://www.walsh.ws/usb_reload.txt
>>>>
>>>> In usb_reload.txt I first unload the ohci_hcd module then insert the
>>>> cardbus card.
>>>>
>>>> In usb_hang.txt the ohci_hcd module is already loaded when I insert the
>>>> card.
>>>>
>>>> I can not say at this time if it works on an i386 machine, as soon as I
>>>> can set
>>>> one up I will test it out.
>>>>
>>>> Brian
>>>>
>>>>
>>> After looking through the logs again it appears this may be an Arm related
>>> problem. The dmabounce message is saying there is a device on the pci bus
>>> and
>>> then the drivers attach. When it fails the dmabounce message is coming
>>> after
>>> the usb drivers have attached to the device. Anyway I am posting this
>>> problem
>>> over to the arm-kernel list as well.
>>>
>>
>> Ok I am still not sure where the problem exactly lies but here is the fix I
>> came
>> up with.
>>
>> I moved the call to platform_notify up in the call to device_add. This
>> allows
>> the device to fully attach to the system before the driver starts to mess
>> with
>> it. I don't know if it is the best solution but it works for my hardware.
>>
>> Comments?
>
> What does your platform_notify() do? What arch is this? Pointers to
> code anywhere?
>
> And as it looks like only ppc and arm platforms use this callback, you
> should really check with the maintainers of those arches before I could
> accept a patch like this.
>
> thanks,
>
> greg k-h
>
I am running on an arm ixp425 coyote based arch. It looks like the code
allocates some DMA buffers for the device in arch/arm/common/dmabounce.c
dmabounce_register_dev(). When the driver is already loaded the driver starts
to work with the device before the buffers are allocated.
I have posted this problem over to the arm-kernel list as well after
reevaluating the problem from the logs that I posted. I have not heard anything
back from there as of yet. I was just reposting to this list to follow up on
what I had found. I was just hoping that the solution would not get any "your
board will explode if you do that" comments. :)
The initial solution of having to unload the ohci_hcd driver led me to believe
that it was usb related, which it no longer seems to be. I just hate searching
list archives and finding similar problems that don't ever come to a resolution.
If you want we can just say it is up to the arm maintainers for now.
Thanks
Brian
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