Re: ohci1394 problem (MMIO broken) (was 2.6.25-rc6-git6: Reported regressions from 2.6.24) [Bug 10080]

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

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/