Re: 2.4.22 USB problem (uhci)

From: Jan Rychter
Date: Fri Sep 19 2003 - 17:32:13 EST


>>>>> "Greg" == Greg KH <greg@xxxxxxxxx> 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.
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