while battling to get my Praktica DC1.3 digital camera to work I noticed what seems to be a problem in the usb-storage driver.
I am using kernel 2.4.21-rc6 with the ACPI-patches applied. The camera uses transparent SCSI and bulk-only transport,
In function usb_stor_transfer_partial in drivers/usb/storage/transport.c the case of
'result == -EPIPE'
does not seem to be handled properly. The pipe gets reinitialized but no return code is set, so the catch-all error handler gets invoked and returns US_BULK_TRANSFER_FAILED.
I noticed that whenever -EPIPE occurs in this method the bcs->Tag content gets changed, too, finally resulting in a bus reset:
<taken from logs> usb-storage: Command INQUIRY (6 bytes) usb-storage: 12 00 00 00 ff 00 00 00 cb 07 00 00 usb-storage: Invoking Mode Translation usb-storage: Bulk command S 0x43425355 T 0x1 Trg 0 LUN 0 L 255 F 128 CL 6 usb-storage: Bulk command transfer result=0 usb-storage: usb_stor_transfer_partial(): xfer 255 bytes usb-storage: usb_stor_bulk_msg() returned -32 xferred 0/255 usb-storage: clearing endpoint halt for pipe 0xc0008280 usb-storage: usb_stor_clear_halt: result=0 usb-storage: usb_stor_transfer_partial(): unknown error usb-storage: Bulk data transfer result 0x2 usb-storage: Attempting to get CSW... usb-storage: Bulk status result = 0 usb-storage: Bulk status Sig 0x53425355 T 0x143 R 0 Stat 0x1 usb-storage: Bulk logical error usb-storage: -- transport indicates error, resetting usb-storage: Bulk reset requested
It seems to me that the -EPIPE case should try to transfer the data propery after taking care of the pipe, however as I don't really have any clue about how the protocol is working I was not very successful.
At least I managed to get my camera recognized by adding a return value of US_BULK_TRANSFER_GOOD to the -EPIPE case and allowing the changed bcs-Tag content. As the data itself was not properly transfered, a mount was possible, but the directory content didn't look pretty.
By the way, I was able to mount the camera successfully with the original transport.c, but that took ages since after about every other command a bus reset was initiated...
Any help would be appreciated.
Best wishes,
Martin.
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