On Tue, 2003-11-11 at 15:23, Alan Stern wrote: > On Tue, 11 Nov 2003, Henry Culver wrote: > > > I am in the process of writing a device driver for a device which is a > > combination vacuum flourescent display and ir receiver. The driver is > > functional, but has some problems. > > > > The device has a single configuration, and single interface with 2 endpoints. > > The endpoints are transfer type "interrupt". > > > > My open routine allocates 2 urb's (one for each endpoint, in and out) and > > fills them with usb_fill_int_urb. I have an "in" callback routine and an > > "out" callback routine. > > > > I can read ir byte codes from the device and write characters to the display > > including control codes which position subsequent character writes, clear > > the display and set brightness. > > > > My problem is that I cannot seem to reuse the out urb. When my write_callback > > routine is called, the urb->status is 0, but another write to the device > > blocks and the urb->status is thereafter -EINPROGRESS. If in my callback > > routine I usb_unlink_urb, usb_free_urb and then usb_alloc_urb(0) and > > re-initialize the structure, everything behaves correctly. > > I don't understand. What do you mean "another write to the device > blocks"? If the write blocked, how would you know what urb->status was > afterwards? -- your machine would be locked up. After submission, > usb->status is _supposed_ to be -EINPROGRESS; it stays that value more or > less until it has completed.
Sorry for the missing details. It's linux-2.4.21. When I say it blocks I mean that I call interruptible_sleep_on in the write routine and wake_up in the write_callback routine. If I remove the interruptible_sleep_on, the write never seems to finish (the status never changes from EINPROGRESS and the data never appears on the display). That is to say, the write_callback doesn't get called for the 2nd write. As near as I can tell the 2nd urb is never finishing. My next step I guess is to printk the various fields in the urb and see exactly how a new urb is different from a used one. > > > After each successful write, I have to release and then re-allocate the > > out urb. Shouldn't I be able to reuse it? If so, does anyone have any > > helpful hints as to what might be going on here? > > You certainly should be able to reuse it. What version of Linux and which > host controller driver are you using? If you aren't using 2.6, try it out > and see if it works any better. > > Alan Stern > Thanks, -Henry Culver -Culver Consulting ------------------------------------------------------- This SF.Net email sponsored by: ApacheCon 2003, 16-19 November in Las Vegas. Learn firsthand the latest developments in Apache, PHP, Perl, XML, Java, MySQL, WebDAV, and more! http://www.apachecon.com/ _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
