On Feb 6, 2008 6:42 PM, Alan Stern <[EMAIL PROTECTED]> wrote: > On Wed, 6 Feb 2008, Francis Moreau wrote: > > > Hello, > > > > I'm wondering what this option means and in which cases it's needed. > > > > Thanks for any hint. > > Read the documentation at the top of the source file: > drivers/usb/gadget/file_storage.c.
OK, thanks. I just took a look to modinfo output... > > It's needed in cases where the driver won't work properly without it. :-) > That is, when the controller hardware isn't capable of stalling bulk > endpoints, the parameter tells the driver not to stall them. > I'm trying to port a custom hardware with an embedded UDC. It works so far but I need to pass "stall=0" option to make the mass storage driver work with a windows XP host although the HW can stall any endpoints in theory. If the host is Linux, it works without the need of stall parameter. But I can see strange things happened even in this case: sb-storage: Command MODE_SENSE (6 bytes) usb-storage: 1a 00 3f 00 c0 00 usb-storage: Bulk Command S 0x43425355 T 0x6 L 192 F 128 Trg 0 LUN 0 CL 6 usb-storage: usb_stor_bulk_transfer_buf: xfer 31 bytes g_file_storage gadget: bulk-in set halt usb-storage: Status code 0; transferred 31/31 usb-storage: -- transfer complete usb-storage: Bulk command transfer result=0 usb-storage: usb_stor_bulk_transfer_sglist: xfer 192 bytes, 1 entries usb-storage: Status code -32; transferred 0/192 usb-storage: clearing endpoint halt for pipe 0xc0008280 usb-storage: usb_stor_control_msg: rq=01 rqtype=02 value=0000 index=81 len=0 usb-storage: usb_stor_clear_halt: result = 0 usb-storage: Bulk data transfer result 0x2 usb-storage: Attempting to get CSW... usb-storage: usb_stor_bulk_transfer_buf: xfer 13 bytes usb-storage: Status code -75; transferred 0/13 usb-storage: -- babble usb-storage: Bulk status result = 3 usb-storage: -- transport indicates error, resetting usb-storage: storage_pre_reset Linux host tries this sequence a couple of time with reseting the device between each try and eventually the device work. Does this parameter exist for other class ? IOW can other classes stall bulk endpoint or is it really mass storage class specific ? Thanks -- Francis - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
