uhub: retry attaching device

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uhub: retry attaching device

Alexander Polakov
So I have got this device:
 addr 2: File-backed Storage Gadget, Linux 2.6.24.2-Boeye with s3c-udc

The problem is that when I connect it to PC, it asks for confirmation
and I have to press button on the device. I guess uhub exploration code
timeouts while I'm doing that and gives me "uhub0: device problem,
disabling port 5". With diff attached it works reliably:

umass0 at uhub0 port 5 configuration 1 interface 0 "Linux 2.6.24.2-Boeye with s3c-udc File-backed Storage Gadget" rev 2.00/3.22 addr 2
umass0: using SCSI over Bulk-Only
scsibus4 at umass0: 2 targets, initiator 0
sd2 at scsibus4 targ 1 lun 0: <Linux, File-Stor Gadget, 0322> SCSI2 0/direct removable serial.00850600372041756775
sd2: 1885MB, 512 bytes/sector, 3862393 sectors

Index: uhub.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/uhub.c,v
retrieving revision 1.59
diff -u -p -u -r1.59 uhub.c
--- uhub.c 29 Sep 2011 11:18:01 -0000 1.59
+++ uhub.c 20 Jan 2013 23:33:57 -0000
@@ -349,6 +349,7 @@ uhub_explore(usbd_device_handle dev)
  int speed;
  int port;
  int change, status, reconnect;
+ int i;
 
  DPRINTFN(10, ("uhub_explore dev=%p addr=%d\n", dev, dev->address));
 
@@ -486,10 +487,14 @@ uhub_explore(usbd_device_handle dev)
  speed = USB_SPEED_LOW;
  else
  speed = USB_SPEED_FULL;
- /* Get device info and set its address. */
- err = usbd_new_device(&sc->sc_dev, dev->bus,
-  dev->depth + 1, speed, port, up);
- /* XXX retry a few times? */
+ for (i = 0; i < 3; i++) {
+ /* Get device info and set its address. */
+ err = usbd_new_device(&sc->sc_dev, dev->bus,
+  dev->depth + 1, speed, port, up);
+ usbd_delay_ms(dev, 100);
+ if (!err)
+ break;
+ }
  if (err) {
  DPRINTFN(-1,("uhub_explore: usbd_new_device failed, "
      "error=%s\n", usbd_errstr(err)));

--
Alexander Polakov | plhk.ru

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Re: uhub: retry attaching device

Martin Pieuchot-2
On 21/01/13(Mon) 03:53, Alexander Polakov wrote:

> So I have got this device:
>  addr 2: File-backed Storage Gadget, Linux 2.6.24.2-Boeye with s3c-udc
>
> The problem is that when I connect it to PC, it asks for confirmation
> and I have to press button on the device. I guess uhub exploration code
> timeouts while I'm doing that and gives me "uhub0: device problem,
> disabling port 5". With diff attached it works reliably:
>
> umass0 at uhub0 port 5 configuration 1 interface 0 "Linux 2.6.24.2-Boeye with s3c-udc File-backed Storage Gadget" rev 2.00/3.22 addr 2
> umass0: using SCSI over Bulk-Only
> scsibus4 at umass0: 2 targets, initiator 0
> sd2 at scsibus4 targ 1 lun 0: <Linux, File-Stor Gadget, 0322> SCSI2 0/direct removable serial.00850600372041756775
> sd2: 1885MB, 512 bytes/sector, 3862393 sectors

Could you analyse a bit further why usbd_new_device() is returning an
error? It's certainly when trying to fetch the device descriptor and
as you can see the timing and logic in there is already fishy :)

It would be nice to know what is failing in this function with your
device and properly document it. There's already a ton of hacks and
non standard wait times in it, so I'd prefer no to such a big
workaround.


> Index: uhub.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/usb/uhub.c,v
> retrieving revision 1.59
> diff -u -p -u -r1.59 uhub.c
> --- uhub.c 29 Sep 2011 11:18:01 -0000 1.59
> +++ uhub.c 20 Jan 2013 23:33:57 -0000
> @@ -349,6 +349,7 @@ uhub_explore(usbd_device_handle dev)
>   int speed;
>   int port;
>   int change, status, reconnect;
> + int i;
>  
>   DPRINTFN(10, ("uhub_explore dev=%p addr=%d\n", dev, dev->address));
>  
> @@ -486,10 +487,14 @@ uhub_explore(usbd_device_handle dev)
>   speed = USB_SPEED_LOW;
>   else
>   speed = USB_SPEED_FULL;
> - /* Get device info and set its address. */
> - err = usbd_new_device(&sc->sc_dev, dev->bus,
> -  dev->depth + 1, speed, port, up);
> - /* XXX retry a few times? */
> + for (i = 0; i < 3; i++) {
> + /* Get device info and set its address. */
> + err = usbd_new_device(&sc->sc_dev, dev->bus,
> +  dev->depth + 1, speed, port, up);
> + usbd_delay_ms(dev, 100);
> + if (!err)
> + break;
> + }
>   if (err) {
>   DPRINTFN(-1,("uhub_explore: usbd_new_device failed, "
>       "error=%s\n", usbd_errstr(err)));
>
> --
> Alexander Polakov | plhk.ru
>