Alan,
Finally got a chance to look at this some more. I basically used only the
first portion of your patch. For full_speed devices (I'm assuming this is the
only ones that need this), I call usb_get_descriptor() before
usb_set_address() in order to get the length of the descriptor and max packet
size. It looks like both are needed. Then I use these for the
usb_get_descriptor() after usb_set_address(). This sequence appears to work
with the devices I have been testing with.
I also had to change usb_submit_urb to not check for dev->devnum == 0.
Below is the patch for my version of usb.c.
Let me know if there is something else you want me to try. Thanks for your
help.
Kyle.
--- linux-2.6.0-rmk2/drivers/usb/core/usb.c Wed Dec 17 21:58:49 2003
+++ linux/drivers/usb/core/usb.c Fri Aug 6 16:33:27 2004
@@ -991,6 +992,8 @@
int err = -EINVAL;
int i;
int j;
+ char *buf;
+ int blength;
/*
* Set the driver for the usb device to point to the "generic" driver.
@@ -1020,11 +1027,12 @@
i = 64;
break;
case USB_SPEED_FULL: /* 8, 16, 32, or 64 */
- /* to determine the ep0 maxpacket size, read the first 8
- * bytes from the device descriptor to get bMaxPacketSize0;
- * then correct our initial (small) guess.
+ /* to determine the ep0 maxpacket size, try to read
+ * the device descriptor to get bMaxPacketSize0;
+ * then correct our initial (large) guess.
*/
- // FALLTHROUGH
+ i = 64;
+ break;
case USB_SPEED_LOW: /* fixed at 8 */
i = 8;
break;
@@ -1034,6 +1042,38 @@
dev->epmaxpacketin [0] = i;
dev->epmaxpacketout[0] = i;
+ /*
+ * Some devices fail if the initial get_descriptor after set_addess
+ * does not request actual descriptor length and correct packet size.
+ */
+ if (dev->speed == USB_SPEED_FULL)
+ {
+ buf = kmalloc(64, GFP_KERNEL);
+ if (!buf) {
+ clear_bit(dev->devnum, dev->bus->devmap.devicemap);
+ dev->devnum = -1;
+ return 1;
+ }
+ i = dev->devnum;
+ dev->devnum = 0;
+ err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, buf, 64);
+ if (err < 8) {
+ err("USB device failed initial GET_DESCRIPTOR
(err=%d)", err);
+ clear_bit(i, dev->bus->devmap.devicemap);
+ dev->devnum = -1;
+ kfree(buf);
+ return 1;
+ }
+ dev->devnum = i;
+ dev->epmaxpacketin[0] = dev->epmaxpacketout[0] =
+ ((struct usb_device_descriptor *) buf)->bMaxPacketSize0;
+ blength = ((struct usb_device_descriptor *) buf)->bLength;
+ kfree(buf);
+ }
+ else
+ blength = 8;
+
+
for (i = 0; i < NEW_DEVICE_RETRYS; ++i) {
for (j = 0; j < SET_ADDRESS_RETRYS; ++j) {
@@ -1052,9 +1092,10 @@
wait_ms(10); /* Let the SET_ADDRESS settle */
/* high and low speed devices don't need this... */
- err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
&dev->descriptor, 8);
- if (err >= 8)
+ err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
&dev->descriptor, blength);
+ if (err >= blength)
break;
+
wait_ms(100);
}
@@ -1058,7 +1099,7 @@
wait_ms(100);
}
- if (err < 8) {
+ if (err < blength) {
dev_err(&dev->dev, "device descriptor read/8, error %d\n",
err); goto fail;
}
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