Re: 2.4.22 USB problem (uhci)

[Jan Rychter <jan@rychter.com>]

>>>>> "Greg" == Greg KH <greg@kroah.com> writes:

[...]

 >> Please allow me to restate the original problem:
 >>
 >> -- I usually use uhci instead of usb-uhci, because it is able to go
 >> into "suspend mode" when no devices are plugged, which allows the
 >> CPU to enter C3 states,
 >>
 >> -- usb-uhci eats CPU power by keeping it in C2 constantly because of
 >> busmastering DMA activity, therefore being much less useful,
 >>
 >> -- uhci generally works for me just fine, but breaks in one
 >>    particular
 >> case, when removing the device causes a strange message to be
 >> printed and the system being unable to use the C3 states again,
 >> until uhci is unloaded and reloaded back again.
 >>
 >> Just as a reminder, this message is:
 >>
 >> uhci.c: efe0: host controller halted. very bad
 >>
 >> I hope if the message says "very bad", then this is something that
 >> can be fixed. I was therefore reporting a problem with "uhci" and
 >> kindly asking for help.

 Greg> Ok, sorry for the confusion.  No I don't know of a fix for this
 Greg> problem, but one just went into the 2.6 kernel tree for the
 Greg> uhci-hcd driver that you might want to take a look at that fixed
 Greg> a problem almost exactly like this.

Greg,

I've looked at uhci.c, the message comes from line 2461, in
uhci_interrupt. But there is no chance I will be able to fix it without
first understanding thoroughly how uhci.c works.

So I guess this goes into my "unfixed Linux bugs" bin.

--J.