hi Alan:
2016-03-04 23:25 GMT+08:00 Alan Stern <[email protected]>:
> On Fri, 4 Mar 2016, yoma sophian wrote:
>
>> BTW, when I disable BH support in hcd driver.
>> I get below recursion of spin lock sometimes.
>> Did I missing anything once disable BH?
>
> Yes, you missed a very important fact: ehci-hcd _requires_ BH support!
if so, why we still keep below part of code that will never run under
BH enabled.

        if (!hcd_giveback_urb_in_bh(hcd) && !is_root_hub(urb->dev)) {
                __usb_hcd_giveback_urb(urb);
                return;
        }
Appreciate your kind explanation,
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