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 Gr??en
David Engraf
Netcom Sicherheitstechnik GmbH
Rheinallee 189
55120 Mainz
Tel: +49 6131 6305 0
Fax: +49 6131 6305 40
Email: [email protected]
Sitz der Gesellschaft: Mainz
Registergericht: Amtsgericht Mainz, 14HRB3411
Gesch?ftsf?hrer: Peter Otto
On Wed, Aug 01, 2007 at 09:21:12AM +0200, David Engraf wrote:
> 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.
This sounds like a BIOS bug.
> 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.
We need to do this early to handle a wide range of machines that do very
nasty things if we do not grab the device as early as possible. Even if
we do not ever get around to loading that usb driver.
Yeah, hardware sucks at times :(
thanks,
greg k-h
Greg KH schrieb:
> On Wed, Aug 01, 2007 at 09:21:12AM +0200, David Engraf wrote:
>
>> 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.
>>
>
> This sounds like a BIOS bug.
>
I think so too and I have to talk to Jetway/VIA what there is going wrong.
>
>> 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.
>>
>
> We need to do this early to handle a wide range of machines that do very
> nasty things if we do not grab the device as early as possible. Even if
> we do not ever get around to loading that usb driver.
>
> Yeah, hardware sucks at times :(
>
>
Ok, but when we don't habe the driver for the usb controller, I think
the BIOS should control it because
maybe the BIOS found for example a keyboard or mouse and emulates it as
an PS2 keayboard/mouse,
so we could use it without the usb driver. I think that's why they
developed the handoff feature.
Are there any known hardware which has problems when we disable the handoff?
> thanks,
>
> greg k-h
>
Thanks
David Engraf
Netcom Sicherheitstechnik GmbH
Rheinallee 189
55120 Mainz
Tel: +49 6131 6305 0
Fax: +49 6131 6305 40
Email: [email protected]
Sitz der Gesellschaft: Mainz
Registergericht: Amtsgericht Mainz, 14HRB3411
Gesch?ftsf?hrer: Peter Otto