Hi Greg,
On 2022/1/26 18:50, Greg KH wrote:
A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
A: No.
Q: Should I include quotations after my reply?
http://daringfireball.net/2007/07/on_top
On Wed, Jan 26, 2022 at 06:22:45PM +0800, 谢泓宇 wrote:
1."What problem?
r8152_submit_rx needs to detach netdev if -ENODEV happened, but -ENODEV will
never happen
because xhci_urb_enqueue only returns -EINVAL if the return value of
xhci_check_args <= 0. So
r8152_submit_rx will will call napi_schedule to re-submit that urb, and this
will cause infinite urb
submission.
Odd line-wrapping...
Sorry about my last reply.
Anyway, why is this unique to this one driver? Why does it not show up
for any other driver?
The whole thing is not about a particular driver. The thing is
xhci_urb_enqueue shouldn't change the return value of xhci_check_args
from -ENODEV to -EINVAL. Many other drivers only check if the return
value of xchi_check_args is <= 0.
The whole point is, if xhci_check_args returns value A, xhci_urb_enqueque
shouldn't return any
other value, because that will change some driver's behavior(like r8152.c).
But you are changing how the code currently works. Are you sure you
want to have this "succeed" if this is on a root hub?
Yes, I'm changing how the code currently works but not on a root hub.
2."So if 0 is returned, you will now return that here, is that ok?
That is a change in functionality.
But this can only ever be the case for a root hub, is that ok?"
It's the same logic, but now xhci_urb_enqueue can return -ENODEV if xHC is
halted.
If it happens on a root hub, xhci_urb_enqueue won't be called.
3."Again, this means all is good? Why is this being called for a root hub?"
It is the same logic with the old one, but now xhci_check_streams_endpoint
can return -ENODEV if xHC is halted.
This still feels wrong to me, but I'll let the maintainer decide, as I
don't understand why a root hub is special here.
Thanks please. usb_submit_urb will call usb_hcd_submit_urb. And
usb_hcd_submit_urb will call rh_urb_enqueue if it's on a root hub
instead of calling hcd->driver->urb_enqueue(which is xhci_urb_enqueue in
this case).
thanks,
greg k-h
thanks,
Hongyu Xie
