Good afternoon, I posted this message on the mailing list on Saturday, but it didn't seem to come through. Here's a re-post - sorry if this ends up being a duplicate. ..tom -------- Original post Hi all, this weekend, I managed to have my first serious go at getting Linux-USB working with 2.3.99pre3. . I have tinkered around with it earlier, but never really tried to get it going. Mostly very successful - thanks to everyone involved to get it to this stage! I did have one problem with OHCI controllers, though. It involves the very early stage, when the device descriptor gets retrieved (8 bytes), and from there on, the whole descriptor gets read. This works like a charm on usb-uhci and uhci, but ohci failed with the message "get descriptor returned 0 bytes, expected 46" (or whatever the real length was). I investigated this to a certain extent. All of the devices involved were low-speed, input-type devices like mice, keyboards, joysticks, ... It seems that, the longer the descriptor was, the more likely it was to fail. In a plain mouse (Logitech N-48), it happened maybe once every 15 or 20 plugs, on a simple joystick with a 30-something byte descriptor, it happened once every ten plugs, on a joystick with a more complicated descriptor (like the one mentioned with 46 bytes) it happend on almost every third plug. Since I am new to the usb sources, I dug around a little bit and played a little with parameters. I haven't come to any conclusion yet, but seem to have stumbled across a line of code which fixes the problem in a very ugly way. Between getting the basic descriptor and the full one in usb.c, I inserted a "wait_ms(16);" (the amount was completely arbitrary). I'm going through the specs, but does anyone (Roman? Aki?) in the mean time have any idea? Once the stack gets over that part, subsequent interrupt transfers work fine. Got the keyboard and mouse working (hid, kbddev, mousedev). Apart from the odd Oops during un-plug, things ran smooth. Success stories: - Also, after I made the 16-ms wait fix for OHCI, I was feeling daring and hooked up my digital camera (Toshiba PDR-M4, apparently having some Iomega-based SCSI interface, judging from the windows drivers). Modprobed usb-storage, mounted the flash card with a vfat filesystem (would only do it read-only), and there they were - my pictures in all of their beauty! - Interrupt out: I believe this transfer type has been exercised least, mainly because there are hardly any int-out devices. Well, we (@logitech) have a few, and I went ahead and wrote a little driver which talks over int-out. Success! Works on uhci, usb-uhci, usb-ohci, no glitches or weirdnesses. Just thought I'd mention it, ..tom --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
