hi alan:
2011/1/2 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>:
> On Sat, 1 Jan 2011, vichy wrote:
>
>> after tracing the source code, I found usb_hcd_giveback_urb will be
>> called in ehci_urb_done when interrupt happen and that is the normal
>> path.
>
> Yes.
>
>> But what makes me confuse is when timeout happen such as
>> wait_for_completion_timeout in usb_start_wait_urb, which function will
>> call usb_hcd_giveback_urb and bring -2 to it originally I guess maybe
>> the ehci_watchdog, but I think it is not, because the function has no
>> idea of the time out parameter, right?
>
> No, not ehci_watchdog. It's the same function as above, ehci_urb_done.
Thanks for your help :)
after studying the source again, I guess when timeout happen, the
ehci_urb_done is called by end_unlink_async to screen out the previous
commands.
Why I ask this question is I found something abnormal
I purposely dump the the token of the qtd in timeout urb under
qh_completions and it shows:
(I set a bit when driver fail on wait_for_completion_timeout, and
check this bit in qh_completions)
urb 84718200 toke 0x80000e00
ehci -ehci.0: ehci_urb_done 1 urb 84718200 ep0out status -150 len 0/0
usb 2-1: ifconfig timed out on ep0out len=0/0
The active bit is 0, and if I remember correctly this bit should be
already set in qh_urb_transaction.
Meanwhile, I also add message as below:
wmb ();
dummy->hw_token = token;
if(token != dummy->hw_token)
printk("Not identy token=0x%x, dummy->hw_token=0x%x\n",token,
dummy->hw_token);
but i didn't see it in the log.
I also grep the source and I didn't find any place to clear this bit.
Did I miss anything or I need to do more experiments?
appreciate your kind help :)
vichy
>
>> BTW, under what circumstance the status of urb will be -150?
>> I grep include/linux and didn't find amy error number which is -150.
>> appreciate your kind help :)
>
> include/linux is not the right directory. You should be looking in
> arch/*/include/asm and include/asm-generic/errno*.h. If you are using
> an x86 architecture then the URB status should never be -150. But if
> you are using a MIPS architecture then -150 is the same as
> -EINPROGRESS.
>
> Alan Stern
>
>
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