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SubjectRE: How to find if BIOS has already enabled the device
Date
From
>I am trying to trace the root cause of an annoying problem 
>with a USB Storage
>device -
>
>My laptop's BIOS supports booting from USB devices. I have attached an
>external USB HDD to a USB 2.0 port. If I boot Linux with the
>HDD attached and
>powered on, load of OHCI-HCD module hangs the machine for
>around 2 minutes -
>after that it recovers and all is fine. I have tried different distros
>without luck, but while installing debian, I figured out that the hang
>happens after ohci-hcd calls pci_enable_device() for the USB
>controller.
>
>This does not happen when the boot is complete. I.e. if I
>attach the HDD after
>boot is complete (BIOS did not get a chance to enable it
>beforehand) load of
>ohci-hcd (during and after boot) does not hang the machine.
>
>I think since the machine supports booting from USB HDD, the
>BIOS must be
>enabling the USB controller and attached device early during
>boot, and when
>ohci-hcd tries to re-enable it, it doesn't like it and leads
>to a hang.

See if 'usb-handoff' as a kernel parameter makes it any better.

Aleks.

>
>My question - Is it possible to detect if the USB controller
>is already
>enabled and skip enabling it second time?
>
>Thanks
>
>Parag
>-
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