ChangeSet 1.1713.7.5, 2004/04/07 16:51:28-07:00, [EMAIL PROTECTED]
[PATCH] USB: retry some descriptor fetches
This helps Linux handle certain enumeration problems better,
by retrying most stalled descriptor fetches; on some devices,
those indicate temporary problems. This match makes at least
one such (old) device enumerate reliably.
drivers/usb/core/message.c | 17 ++++++++++++++---
1 files changed, 14 insertions(+), 3 deletions(-)
diff -Nru a/drivers/usb/core/message.c b/drivers/usb/core/message.c
--- a/drivers/usb/core/message.c Wed Apr 14 14:33:56 2004
+++ b/drivers/usb/core/message.c Wed Apr 14 14:33:56 2004
@@ -572,13 +572,16 @@
memset(buf,0,size); // Make sure we parse really received data
while (i--) {
- /* retries if the returned length was 0; flakey device */
+ /* retry on length 0 or stall; some devices are flakey */
if ((result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
(type << 8) + index, 0, buf, size,
HZ * USB_CTRL_GET_TIMEOUT)) > 0
- || result == -EPIPE)
+ || result != -EPIPE)
break;
+
+ dev_dbg (&dev->dev, "RETRY descriptor, result %d\n", result);
+ result = -ENOMSG;
}
return result;
}
@@ -1244,7 +1247,7 @@
/* get langid for strings if it's not yet known */
if (!dev->have_langid) {
- err = usb_get_string(dev, 0, 0, tbuf, 4);
+ err = usb_get_descriptor(dev, USB_DT_STRING, 0, tbuf, 4);
if (err < 0) {
dev_err (&dev->dev,
"string descriptor 0 read error: %d\n",
@@ -1268,11 +1271,19 @@
*/
err = usb_get_string(dev, dev->string_langid, index, tbuf, 2);
+ if (err == -EPIPE) {
+ dev_dbg(&dev->dev, "RETRY string %d read/%d\n", index, 2);
+ err = usb_get_string(dev, dev->string_langid, index, tbuf, 2);
+ }
if(err<2)
goto errout;
len=tbuf[0];
err = usb_get_string(dev, dev->string_langid, index, tbuf, len);
+ if (err == -EPIPE) {
+ dev_dbg(&dev->dev, "RETRY string %d read/%d\n", index, len);
+ err = usb_get_string(dev, dev->string_langid, index, tbuf, len);
+ }
if (err < 0)
goto errout;
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