[Bug 1001024] STM32 USB driver and proposed USB API change

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John Dallaway <john@dallaway.org.uk> changed:

           What    |Removed                     |Added
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         AssignedTo|unassigned@bugs.ecos.source |john@dallaway.org.uk
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--- Comment #12 from John Dallaway <john@dallaway.org.uk> 2010-10-15 14:51:27 BST ---
Chris, thank you for the updated driver. The cdc-acm driver on my Linux box is
now reporting "Zero length descriptor references":

Oct 15 13:11:27 cog kernel: usb 4-1: new full speed USB device using uhci_hcd
and address 28
Oct 15 13:11:37 cog kernel: usb 4-1: configuration #1 chosen from 1 choice
Oct 15 13:11:37 cog kernel: drivers/usb/class/cdc-acm.c: Zero length descriptor
references
Oct 15 13:11:37 cog kernel: 
Oct 15 13:11:37 cog kernel: cdc_acm: probe of 4-1:1.0 failed with error -22

This seems to be widely reported on the net with random ACM hardware so I have
switched back to CYGDAT_IO_USB_SLAVE_CLASS_TYPE == "generic" for the time
being.

With the eCos "generic" USB serial support, I'm issuing:

  modprobe usbserial vendor=0xffff product=0x0001

and seeing:

Oct 15 13:49:49 cog kernel: usb 4-1: new full speed USB device using uhci_hcd
and address 35
Oct 15 13:49:59 cog kernel: usb 4-1: configuration #1 chosen from 1 choice
Oct 15 13:49:59 cog kernel: usbserial_generic 4-1:1.0: generic converter
detected
Oct 15 13:49:59 cog kernel: usb 4-1: generic converter now attached to ttyUSB0

So far, so good.

I can connect to /dev/ttyUSB0 using minicom and send/receive chars over USB.

The remaining problem is that every other char I receive on the eCos side is a
copy of the previous character received. If I type "abcdefgh" into minicom,
eCos receives "?bbddffh". The very first char received is random. The timing of
all received characters is as expected (immediately after hitting the key). The
transmission of chars from eCos to minicom is working correctly.

Can you see how this issue might arise with your latest STM32 USB driver code?
Is there some further tracing I could add to debug this?

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