[PATCH] USB: Patch to make usbmon to print control setup packets
Make usbmon to print Setup packets of Control transfers. This is useful
when debugging enumeration issues.
This is a change to the trace format which is not fully compatible.
A parser has to look at the data length word now. If that word is
a character like 's', read setup packet before proceeding with data.
I decided not to bump the API tag for this because not many such
parsers exist at this point.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/usb/usbmon.txt b/Documentation/usb/usbmon.txt
index 2f8431f..f1896ee 100644
--- a/Documentation/usb/usbmon.txt
+++ b/Documentation/usb/usbmon.txt
@@ -101,6 +101,13 @@
or 3 and 2 positions, correspondingly.
- URB Status. This field makes no sense for submissions, but is present
to help scripts with parsing. In error case, it contains the error code.
+ In case of a setup packet, it contains a Setup Tag. If scripts read a number
+ in this field, the proceed to read Data Length. Otherwise, they read
+ the setup packet before reading the Data Length.
+- Setup packet, if present, consists of 5 words: one of each for bmRequestType,
+ bRequest, wValue, wIndex, wLength, as specified by the USB Specification 2.0.
+ These words are safe to decode if Setup Tag was 's'. Otherwise, the setup
+ packet was present, but not captured, and the fields contain filler.
- Data Length. This is the actual length in the URB.
- Data tag. The usbmon may not always capture data, even if length is nonzero.
Only if tag is '=', the data words are present.
@@ -125,25 +132,31 @@
String data_str = st.nextToken();
int len = data_str.length() / 2;
int i;
+ int b; // byte is signed, apparently?! XXX
for (i = 0; i < len; i++) {
- data[data_len] = Byte.parseByte(
- data_str.substring(i*2, i*2 + 2),
- 16);
+ // data[data_len] = Byte.parseByte(
+ // data_str.substring(i*2, i*2 + 2),
+ // 16);
+ b = Integer.parseInt(
+ data_str.substring(i*2, i*2 + 2),
+ 16);
+ if (b >= 128)
+ b *= -1;
+ data[data_len] = (byte) b;
data_len++;
}
}
}
}
-This format is obviously deficient. For example, the setup packet for control
-transfers is not delivered. This will change in the future.
+This format may be changed in the future.
Examples:
-An input control transfer to get a port status:
+An input control transfer to get a port status.
-d74ff9a0 2640288196 S Ci:001:00 -115 4 <
-d74ff9a0 2640288202 C Ci:001:00 0 4 = 01010100
+d5ea89a0 3575914555 S Ci:001:00 s a3 00 0000 0003 0004 4 <
+d5ea89a0 3575914560 C Ci:001:00 0 4 = 01050000
An output bulk transfer to send a SCSI command 0x5E in a 31-byte Bulk wrapper
to a storage device at address 5:
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index 755a457..26266b30 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -19,11 +19,16 @@
#define DATA_MAX 32
/*
+ * Defined by USB 2.0 clause 9.3, table 9.2.
+ */
+#define SETUP_MAX 8
+
+/*
* This limit exists to prevent OOMs when the user process stops reading.
*/
#define EVENT_MAX 25
-#define PRINTF_DFL 120
+#define PRINTF_DFL 130
struct mon_event_text {
struct list_head e_link;
@@ -33,7 +38,9 @@
unsigned int tstamp;
int length; /* Depends on type: xfer length or act length */
int status;
+ char setup_flag;
char data_flag;
+ unsigned char setup[SETUP_MAX];
unsigned char data[DATA_MAX];
};
@@ -64,6 +71,22 @@
* This is called with the whole mon_bus locked, so no additional lock.
*/
+static inline char mon_text_get_setup(struct mon_event_text *ep,
+ struct urb *urb, char ev_type)
+{
+
+ if (!usb_pipecontrol(urb->pipe) || ev_type != 'S')
+ return '-';
+
+ if (urb->transfer_flags & URB_NO_SETUP_DMA_MAP)
+ return 'D';
+ if (urb->setup_packet == NULL)
+ return 'Z'; /* '0' would be not as pretty. */
+
+ memcpy(ep->setup, urb->setup_packet, SETUP_MAX);
+ return 0;
+}
+
static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
int len, char ev_type)
{
@@ -90,7 +113,6 @@
/*
* Bulk is easy to shortcut reliably.
- * XXX Control needs setup packet taken.
* XXX Other pipe types need consideration. Currently, we overdo it
* and collect garbage for them: better more than less.
*/
@@ -144,6 +166,7 @@
/* Collecting status makes debugging sense for submits, too */
ep->status = urb->status;
+ ep->setup_flag = mon_text_get_setup(ep, urb, ev_type);
ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type);
rp->nevents++;
@@ -299,10 +322,25 @@
default: /* PIPE_BULK */ utype = 'B';
}
cnt += snprintf(pbuf + cnt, limit - cnt,
- "%lx %u %c %c%c:%03u:%02u %d %d",
+ "%lx %u %c %c%c:%03u:%02u",
ep->id, ep->tstamp, ep->type,
- utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe),
- ep->status, ep->length);
+ utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe));
+
+ if (ep->setup_flag == 0) { /* Setup packet is present and captured */
+ cnt += snprintf(pbuf + cnt, limit - cnt,
+ " s %02x %02x %04x %04x %04x",
+ ep->setup[0],
+ ep->setup[1],
+ (ep->setup[3] << 8) | ep->setup[2],
+ (ep->setup[5] << 8) | ep->setup[4],
+ (ep->setup[7] << 8) | ep->setup[6]);
+ } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */
+ cnt += snprintf(pbuf + cnt, limit - cnt,
+ " %c __ __ ____ ____ ____", ep->setup_flag);
+ } else { /* No setup for this kind of URB */
+ cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->status);
+ }
+ cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->length);
if ((data_len = ep->length) > 0) {
if (ep->data_flag == 0) {