Re: [Libusb-devel] openusb_get_configuration.

[Fenye F. B. <bao...@gm...>]

The initial value of configuration is set at linux_open(). I think that the
value of hdev->idev->cur_config should be set to 1 here, as follows, instead
of 0. This default configuration value (zero) will cause the errors in
check_req_valid() in the case that debug level is set at 5.

Index: src/linux.c
===================================================================
--- src/linux.c    (revision 164)
+++ src/linux.c    (working copy)
@@ -189,7 +189,7 @@
         return (OPENUSB_NO_RESOURCES);
     }

-    hdev->idev->cur_config = 0;
+    hdev->idev->cur_config = 1;
     hdev->config_value = 1;

     /* link the handle and the usbi_device */



On Wed, Aug 27, 2008 at 1:30 AM, Lou <lou...@fi...>wrote:

> On Mon, Aug 25, 2008 at 10:02:03PM -0400, Michael Lewis wrote:
> > On Sat, Aug 23, 2008 at 2:13 AM, Lou <lou...@fi...
> >wrote:
> >
> > > openusb_get_configuration and openusb_set_configuration are documented
> > > thusly:
> > >
> > > > openusb_get_configuration, openusb_set_configuration -- Get the
> current
> > > > bConfigurationValue of a device, Set a device's bConfigurationValue
> > >
> > > I have found that, in practice, it doesn't work like that.
> [...]
>
> > > For some reason, this only showed up when I was both setting the
> > > configuration and had debug set at level 5.
> >
> > I will take a look at that, but I can tell you that when you have the
> debug
> > level set to less than 5, then check_req_valid doesn't really do much, so
> > that's probably why you're not seeing the error with other debug levels.
>
> Cool.
> Yeah; I found something that suggested that during my debugging, but
> when it became time to write it up, I couldn't find that anymore to cite.
> A quick grep showed check_req_valid to be the only place where
> openusb_get_configuration is used internally.
>
> Something I found while trying to figure this out was that when I had
> set the configuration (thus check_req_valid was using the wrong index),
> it queried the device for a configuration with that index, which was
> wrong, and the device told it so by stalling the control endpoint, and
> that error wasn't getting handled properly somewhere.  This appears to be
> what was causing the hangs.  The actual error was -32 (EPIPE).
>
> cacb7880 2504553371 S Ci:2:020:0 s 80 06 0201 0000 0008 8 <
> cacb7880 2504555034 C Ci:2:020:0 -32 0
>
>
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-- 
Best regards!

Fenye Felix Bao
bao...@gm...