On Sat, 18 Feb 2006, Andrew Fuller wrote: > On 2/18/06, Alan Stern <[EMAIL PROTECTED]> wrote: > > On Sat, 18 Feb 2006, Andrew Fuller wrote: > > > > That program does nothing but ask the device to send its device > > descriptor. Linux does that already as one of the first things whenever a > > new device is plugged in. It's not clear why the program should make your > > Joypad work; it must work around some defect in the device. > > > > Alan Stern > > I expected as much. And it wouldn't surprise me if there is some bug > in the hardware. Perhaps it's expecting a probe to it after a certain > stage before turning "on" or perhaps it can't handle some probe that > is being done to it by default, which throws it in to this weird > locked state until another probe for the descriptor which then resets > it? Is there some way I could debug this?
Debug the device? I don't know how. Maybe the manufacturer would tell you about any quirks. > Where can I find the code > in Linux which is doing this? The code which is doing what? Several different things happen when the device is first detected. The initial ones are in drivers/usb/core/hub.c, later ones are in drivers/usb/core/config.c and drivers/usb/core/message.c, and then there are still others in drivers/usb/input/hid-core.c. > If I can duplicate that process under > my own control I could find out at least whether it starts off in a > working state, then dies, or begins dead until a delayed device > descriptor probe. I don't think you can duplicate that series of events under your own control. Not at all easily, anyway. And even if you did, the information you got probably wouldn't help very much. Clearly the device does start off in a working state; otherwise it wouldn't even show up in /proc/bus/usb/devices. One thing you can do is find out exactly what data is being sent back and forth over the USB connection. Use the usbmon facility, described in Documentation/usb/usbmon.txt. Even so, I don't see how this will help. Alan Stern ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
