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SubjectRe: ohci1394 problem (MMIO broken) (was 2.6.25-rc6-git6: Reported regressions from 2.6.24) [Bug 10080]
H. Peter Anvin wrote at 
http://bugzilla.kernel.org/show_bug.cgi?id=10080#c9 :
> I'm confused about this. I looked at the original threads, and what really
> stands out to me is that the original reporter had two drivers loaded for the
> same hardware (firewire-ohci and ohci1394.) *In the best case* there is a
> fundamental race condition there, meaning unpredictable behaviour would be the
> norm.


Hmm, right -- I didn't see this until now. Today's dmesg:
http://bugzilla.kernel.org/attachment.cgi?id=15397&action=view
[ 1.236587] firewire_ohci: Failed to remap registers
[ 243.640549] ohci1394: fw-host0: Get PHY Reg timeout
(etc.)

However, the two drivers for the same device don't seem to be the
problem. Looks like firewire-ohci was attempted to be bound to the
controller much earlier than ohci1394. The error message means that
firewire-ohci's pci_request_region() succeeded but pci_iomap() failed,
hence the pci_driver.probe failed, hence firewire-ohci wasn't bound to
the device, hence subsequent loading of ohci1394 (manually, I presume)
was a valid action.

IOW firewire-ohci was indeed already loaded, but not bound to the device
because of the .probe failure; and ohci1394 was loaded much later.

Same thing in the report in February:
http://lkml.org/lkml/2008/2/23/244
[ 1.326958] firewire_ohci: Failed to remap registers
[ 856.943807] ohci1394: fw-host0: Get PHY Reg timeout
(here: ohci1394 manually loaded by insmod)

(Let's see if bugme-daemon captures this...)
--
Stefan Richter
-=====-==--- --== =-==-
http://arcgraph.de/sr/


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