On Tuesday 28 September 2004 19:08, David Woodhouse wrote:
> On Tue, 2004-09-28 at 19:05 +0200, Duncan Sands wrote:
> > > It appears to confirm my belief that the userspace program is doing
> > > _precisely_ what both Duncan's and my kernel versions do.... nothing but
> > > the bulk transfer. I've already triple-checked the endpoints and the
> > > data. We show a CRC on the data and print the length. I've even done a
> > > hex dump of the start and end of the data in my paranoia.
> >
> > Doesn't the user-space program do a usb_set_configuration? (It used to).
> > Maybe that resets the device.
> >
> > Just a passing thought,
>
> /*
> pusb_set_configuration() triggers hotplug. All previous interfaces
> are removed and all new interfaces are added. In our example, it
> makes 6 calls to usb.agent (tested on 2.6.5).
>
> Both in 2.4 and 2.6 kernels, there is an initial call to
> pusb_set_interface() to set the default interface before calling
> hotplug. So, all call to pusb_set_interface() are useless since
> there is only one interface.
> */
> #if 0
> if (pusb_set_configuration(fdusb, 1) < 0) {
> report(0, REPORT_ERROR, "pusb_set_configuration 1");
> return(-1);
> }
> #endif
>
> I believe that comment is true even with
> s/calling hotplug/calling the udsl_usb_probe() routine/
proc_setconfig (devio.c):
...
/* SET_CONFIGURATION is often abused as a "cheap" driver reset,
* so avoid usb_set_configuration()'s kick to sysfs
*/
if (status == 0) {
if (actconfig && actconfig->desc.bConfigurationValue == u)
status = usb_reset_configuration(ps->dev);
else
status = usb_set_configuration(ps->dev, u);
}
...
/**
* usb_reset_configuration - lightweight device reset
* @dev: the device whose configuration is being reset
*
* This issues a standard SET_CONFIGURATION request to the device using
* the current configuration. The effect is to reset most USB-related
* state in the device, including interface altsettings (reset to zero),
* endpoint halts (cleared), and data toggle (only for bulk and interrupt
* endpoints). Other usbcore state is unchanged, including bindings of
* usb device drivers to interfaces.
*
* Because this affects multiple interfaces, avoid using this with composite
* (multi-interface) devices. Instead, the driver for each interface may
* use usb_set_interface() on the interfaces it claims. Resetting the whole
* configuration would affect other drivers' interfaces.
*
* The caller must own the device lock.
*
* Returns zero on success, else a negative error code.
*/
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