Bug 6940

Summary: USB Gadget File Backup storage driver send wrong information in descriptor. It has been hard coded to send USB 2.0 version. But this becomes problem when the device want USB 1.1
Product: Drivers Reporter: Srinivas Kandagatla (srinivas.kandagatla)
Component: USBAssignee: David Brownell (dbrownell)
Status: REJECTED INVALID    
Severity: normal CC: greg, srinivas.kandagatla
Priority: P2    
Hardware: i386   
OS: Linux   
Kernel Version: 2.6.17 Subsystem:
Regression: --- Bisected commit-id:
Bug Depends on:    
Bug Blocks: 5089    

Description Srinivas Kandagatla 2006-08-01 20:30:12 UTC 
Most recent kernel where this bug did not occur:
Distribution:2.6.17
Hardware Environment: When testing USB gadget File backup storage driver.
Software Environment: Host is another Linux 2.6 PC.
Problem Description: The usb gadget file backup storage driver sends wrong
informaion about the version of USB. It is hard coded to send USB 2.0 as
default. But If the device doesnt support 2.0 and the host supports 2.0 then the
problem comes. It happend with me my device supports only 1.1 and the standard
linux host(2.6 kernel) supports 2.0. and the kernel started sending usb 2.0
commands, for which the device does'nt support. And the result is 
error 
4454927.601000] usb 2-2: new full speed USB device using uhci_hcd and
address 6
[4454932.696000] usb 2-2: unable to read config index 0 descriptor/start
[4454932.696000] usb 2-2: can't read configurations, error -110
[4454932.758000] usb 2-2: new full speed USB device using uhci_hcd and
address 7
[4454937.853000] usb 2-2: unable to read config index 0 descriptor/start
[4454937.853000] usb 2-2: can't read configurations, error -110
[4454937.915000] usb 2-2: new full speed USB device using uhci_hcd and
address 8
[4454942.945000] usb 2-2: unable to read config index 0 descriptor/start
[4454942.945000] usb 2-2: can't read configurations, error -110
[4454943.007000] usb 2-2: new full speed USB device using uhci_hcd and
address 9
[4454948.037000] usb 2-2: unable to read config index 0 descriptor/start
[4454948.037000] usb 2-2: can't read configurations, error -110


Steps to reproduce:1) Take a device which supports only 1.1 and install the
module g_file_storage.ko
then try to plug it in 2.6 kernel PC. it dumps messages instead of enumerating it.
I have the fix for this problem to just put the versioning of USB 2.0 info in
the preprocessor  in two places.

#ifdef CONFIG_USB_GADGET_DUALSPEED
        .bcdUSB =               __constant_cpu_to_le16(0x0200),
#else
        .bcdUSB =               __constant_cpu_to_le16(0x0110),
#endif
Comment 1 David Brownell 2006-08-07 16:16:51 UTC 
It's perfectly valid for low or full speed devices to report 
themselves as supporting USB 2.0 ... and Linux hosts don't 
really care. 
 
Problems reading descriptors don't relate to that issue, in 
any case.  They're separate. 
 
You didn't say what peripheral controller your device is using. 
I'll speculate the true bug is that its driver doesn't issue 
protocol stalls (on ep0) correctly.