On Wed, 28 Apr 2004 15:09:39 -0400 (EDT)
Alan Stern <[EMAIL PROTECTED]> wrote:
> > Perhaps I could keep the proc_ioctls from running until the device isn't
> > being used by usb-storage,
>
> That sounds feasible.
It is feasible, but it runs into difficulties with locking order.
I tried to fiddle with the patch Stuart dropped into RH Bugzilla.
I do not have a confidence in it, and unfortunately, the 2.4 development
is closed. I do not want to push it to Marcelo and collect failure
reports at this stage of development.
> > or maybe just make the transport layer of
> > usb-storage retry the clear_feature command for a while if the pipe
> > already has an URB going, instead of simply failing and moving on to
> > the next step without clearing the stall...?
>
> You could do that. Check for -ENXIO error codes and retry in a short
> loop with usb_stor_control_msg().
Stuart, why don't we do something like the attached? Please back out
your patch with semaphores and give it a try, tell me how it went.
Busy waits are bad, I know. HOWEVER, this particular thing is clearly
local in its scope. THEREFORE, if it solves your problem, I can ship
it with Red Hat and even push to Marcelo.
Critique and testing are appreciated.
-- Pete
diff -urN -X dontdiff linux-2.4.26/drivers/usb/storage/transport.c
linux-2.4.26-nip/drivers/usb/storage/transport.c
--- linux-2.4.26/drivers/usb/storage/transport.c 2004-02-26 14:09:59.000000000
-0800
+++ linux-2.4.26-nip/drivers/usb/storage/transport.c 2004-04-30 11:07:18.000000000
-0700
@@ -471,6 +471,7 @@
int result;
int endp = usb_pipeendpoint(pipe) | (usb_pipein(pipe) << 7);
+retry_devio:
result = usb_stor_control_msg(us,
usb_sndctrlpipe(us->pusb_dev, 0),
USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0,
@@ -478,8 +479,21 @@
US_DEBUGP("usb_stor_clear_halt: result=%d\n", result);
/* this is a failure case */
- if (result < 0)
+ if (result < 0) {
+ if (result == -ENXIO) {
+ /*
+ * usb-uhci cannot queue. If lsusb ran on this device
+ * (by a startup script or something), we lose.
+ * But we cannot afford for halts not to clear
+ * for a reason so silly, so we persist rudely.
+ */
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(2);
+ set_current_state(TASK_RUNNING);
+ goto retry_devio;
+ }
return result;
+ }
/* reset the toggles and endpoint flags */
usb_endpoint_running(us->pusb_dev, usb_pipeendpoint(pipe),
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