Greg:
This patch changes the result code returned by the UHCI driver for a
certain class of errors. Under a number of circumstances a USB device is
obliged to send a response packet within a fairly short turn-around time,
typically 1 - 10 microseconds depending on the bus speed. Failure to do
so is a protocol error and should be reported as such, not as a timeout,
which is really a higher-level concept. I believe the EHCI driver already
does this.
I trust nobody will object to the update this patch adds to
Documentation/usb/error-codes.txt, making this more explicit.
In a vaguely related change, the patch corrects the terminology in a few
comments. The parts of a control transfer are called "stages", not
"phases".
Please apply.
Alan Stern
===== error-codes.txt 1.7 vs edited =====
--- 1.7/Documentation/usb/error-codes.txt Wed Jul 17 12:42:00 2002
+++ edited/Documentation/usb/error-codes.txt Mon Feb 23 11:06:03 2004
@@ -70,7 +70,9 @@
(That is, if drivers see this it's a bug.)
-EPROTO (*) a) bitstuff error
- b) unknown USB error
+ b) no response packet received within the
+ prescribed bus turn-around time
+ c) unknown USB error
-EILSEQ (*) CRC mismatch
===== uhci-hcd.c 1.89 vs edited =====
--- 1.89/drivers/usb/host/uhci-hcd.c Thu Feb 19 18:30:19 2004
+++ edited/drivers/usb/host/uhci-hcd.c Mon Feb 23 11:01:45 2004
@@ -781,7 +781,8 @@
/*
* Map status to standard result codes
*
- * <status> is (td->status & 0xFE0000) [a.k.a. uhci_status_bits(td->status)]
+ * <status> is (td->status & 0xF60000) [a.k.a. uhci_status_bits(td->status)]
+ * Note: status does not include the TD_CTRL_NAK bit.
* <dir_out> is True for output TDs and False for input TDs.
*/
static int uhci_map_status(int status, int dir_out)
@@ -792,22 +793,18 @@
return -EPROTO;
if (status & TD_CTRL_CRCTIMEO) { /* CRC/Timeout */
if (dir_out)
- return -ETIMEDOUT;
+ return -EPROTO;
else
return -EILSEQ;
}
- if (status & TD_CTRL_NAK) /* NAK */
- return -ETIMEDOUT;
if (status & TD_CTRL_BABBLE) /* Babble */
return -EOVERFLOW;
if (status & TD_CTRL_DBUFERR) /* Buffer error */
return -ENOSR;
if (status & TD_CTRL_STALLED) /* Stalled */
return -EPIPE;
- if (status & TD_CTRL_ACTIVE) /* Active */
- return 0;
-
- return -EINVAL;
+ WARN_ON(status & TD_CTRL_ACTIVE); /* Active */
+ return 0;
}
/*
@@ -832,7 +829,7 @@
status |= TD_CTRL_LS;
/*
- * Build the TD for the control request
+ * Build the TD for the control request setup packet
*/
td = uhci_alloc_td(uhci, urb->dev);
if (!td)
@@ -990,13 +987,13 @@
if (urbp->short_control_packet) {
tmp = head->prev;
- goto status_phase;
+ goto status_stage;
}
tmp = head->next;
td = list_entry(tmp, struct uhci_td, list);
- /* The first TD is the SETUP phase, check the status, but skip */
+ /* The first TD is the SETUP stage, check the status, but skip */
/* the count */
status = uhci_status_bits(td_status(td));
if (status & TD_CTRL_ACTIVE)
@@ -1037,10 +1034,10 @@
}
}
-status_phase:
+status_stage:
td = list_entry(tmp, struct uhci_td, list);
- /* Control status phase */
+ /* Control status stage */
status = td_status(td);
#ifdef I_HAVE_BUGGY_APC_BACKUPS
@@ -1053,10 +1050,11 @@
return 0;
#endif
+ status = uhci_status_bits(status);
if (status & TD_CTRL_ACTIVE)
return -EINPROGRESS;
- if (uhci_status_bits(status))
+ if (status)
goto td_error;
return 0;
@@ -1403,7 +1401,8 @@
urb->iso_frame_desc[i].actual_length = actlength;
urb->actual_length += actlength;
- status = uhci_map_status(uhci_status_bits(td_status(td)),
usb_pipeout(urb->pipe));
+ status = uhci_map_status(uhci_status_bits(td_status(td)),
+ usb_pipeout(urb->pipe));
urb->iso_frame_desc[i].status = status;
if (status) {
urb->error_count++;
===== uhci-hcd.h 1.23 vs edited =====
--- 1.23/drivers/usb/host/uhci-hcd.h Thu Feb 19 11:15:06 2004
+++ edited/drivers/usb/host/uhci-hcd.h Mon Feb 23 10:40:16 2004
@@ -141,7 +141,7 @@
TD_CTRL_BABBLE | TD_CTRL_CRCTIME | TD_CTRL_BITSTUFF)
#define uhci_maxerr(err) ((err) << TD_CTRL_C_ERR_SHIFT)
-#define uhci_status_bits(ctrl_sts) ((ctrl_sts) & 0xFE0000)
+#define uhci_status_bits(ctrl_sts) ((ctrl_sts) & 0xF60000)
#define uhci_actual_length(ctrl_sts) (((ctrl_sts) + 1) & TD_CTRL_ACTLEN_MASK) /*
1-based */
/*
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