Messages in this thread | | | Date | Wed, 01 Aug 2007 09:21:12 +0200 | From | David Engraf <> | Subject | Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured |
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At the moment I have a Jetway/VIA Mainboard which seems to have a problem with the handoff. Evenwhen I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not cleared. I think this is a BIOS bug and I will have to talk to Jetway/VIA. On the other hand, I don't need the EHCI controller in my kernel, so I think the kernel shouldn't take the handover for the EHCI controller like other OS which do not have an usb driver and so don't know that there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.
David Engraf
Alan Stern schrieb: > On Tue, 31 Jul 2007, David Engraf wrote: > > >> When CONFIG_USB_UHCI_HCD, CONFIG_USB_OHCI_HCD or CONFIG_USB_EHCI_HCD is >> not configured we don't need to call the quirk_usb_handoff_xxxx function >> in driver/usb/host/pci_quiks.c. >> >> I think the kernel shouldn't take the control over the usb controller >> when we don't have the driver for it, >> so with this patch the kernel takes the control only when the driver is >> configured. >> > > Have you found a system where this really improves behavior or is it > just theoretical? > > There _is_ a theoretical reason for running the handoff routines even > when the corresponding driver isn't configured. Namely, at startup the > controller will be in some undetermined state as a result of usage by > the firmware. Resetting it to a known idle state is a good idea. > > Bear in mind that on some systems, not performing the handoff has > caused interrupt storms during startup. > > Alan Stern > > >
-- Mit freundlichen Grüßen
David Engraf
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