Re: What to do with all of the USB UHCI drivers in the kernel ?

["Maksim (Max) Krasnyanskiy" <maxk@qualcomm.com>]

>IMO, I think testing with usb-uhci.c and uhci.c is still useful, but
>testing with the -hcd variants is the most ideal since that will be the
>final code base.

Ok. Here is feedback on 2.5.17 uhci-hcd and usb-uhci-hcd.
I did not notice any difference in behavior. Both have the same 
performance, just like 2.4.19-pre8.

One-shot interrupt transfers are broken in *-hcd drivers. core/hcd.c 
returns EINVAL if urb->interval==0.
My Broadcom FW loader (uses usbdevfs) needs one-shot interrupts. So in 
order to test Broadcom devices
I changed to hcd.c to allow urb->interval==0. With that change uhci-hcd 
works just fine, I can load fw and
use the device. But usb-uhci-hcd kills the machine pretty hard (hw reset 
needed).

Here is a patch for hcd.c.

--- hcd.c.orig  Tue May 21 17:50:09 2002
+++ hcd.c       Tue May 21 17:01:44 2002
@@ -1456,11 +1456,9 @@
          * supports different values... this uses EHCI/UHCI defaults (and
          * EHCI can use smaller non-default values).
          */
-       switch (temp) {
-       case PIPE_ISOCHRONOUS:
-       case PIPE_INTERRUPT:
+       if (urb->interval && (temp == PIPE_ISOCHRONOUS || temp == 
PIPE_INTERRUPT)) {
                 /* too small? */
-               if (urb->interval <= 0)
+               if (urb->interval < 0)
                         return -EINVAL;
                 /* too big? */
                 switch (urb->dev->speed) {

usb-uhci-hcd has to be fixed.
btw It tries to round interval value even thought it's done by hcd.c

So, Bluetooth USB devices should work fine with either usb-uhci-hcd or 
uhci-hcd.
(assuming that above patch is applied and one-shot is fixed in usb-uhci-hcd)

On a side note. Why are URBs still not SLABified ?
Drivers still have those silly urb pools and stuff. I thought you guys were 
gonna fix that.

Max