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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 15:04:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 15:04:26 -0700
commit971f115a50afbe409825c9f3399d5a3b9aca4381 (patch)
treecb42dc07a032e325f22b64d961587c081225c6d6 /Documentation
parent2e270d84223262a38d4755c61d55f5c73ea89e56 (diff)
parent500132a0f26ad7d9916102193cbc6c1b1becb373 (diff)
Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6
* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (172 commits) USB: Add support for SuperSpeed isoc endpoints xhci: Clean up cycle bit math used during stalls. xhci: Fix cycle bit calculation during stall handling. xhci: Update internal dequeue pointers after stalls. USB: Disable auto-suspend for USB 3.0 hubs. USB: Remove bogus USB_PORT_STAT_SUPER_SPEED symbol. xhci: Return canceled URBs immediately when host is halted. xhci: Fixes for suspend/resume of shared HCDs. xhci: Fix re-init on power loss after resume. xhci: Make roothub functions deal with device removal. xhci: Limit roothub ports to 15 USB3 & 31 USB2 ports. xhci: Return a USB 3.0 hub descriptor for USB3 roothub. xhci: Register second xHCI roothub. xhci: Change xhci_find_slot_id_by_port() API. xhci: Refactor bus suspend state into a struct. xhci: Index with a port array instead of PORTSC addresses. USB: Set usb_hcd->state and flags for shared roothubs. usb: Make core allocate resources per PCI-device. usb: Store bus type in usb_hcd, not in driver flags. usb: Change usb_hcd->bandwidth_mutex to a pointer. ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/usb/usbmon.txt42
1 files changed, 9 insertions, 33 deletions
diff --git a/Documentation/usb/usbmon.txt b/Documentation/usb/usbmon.txt
index 66f92d1194c..a4efa0462f0 100644
--- a/Documentation/usb/usbmon.txt
+++ b/Documentation/usb/usbmon.txt
@@ -12,6 +12,10 @@ Controller Drivers (HCD). So, if HCD is buggy, the traces reported by
usbmon may not correspond to bus transactions precisely. This is the same
situation as with tcpdump.
+Two APIs are currently implemented: "text" and "binary". The binary API
+is available through a character device in /dev namespace and is an ABI.
+The text API is deprecated since 2.6.35, but available for convenience.
+
* How to use usbmon to collect raw text traces
Unlike the packet socket, usbmon has an interface which provides traces
@@ -162,39 +166,11 @@ Here is the list of words, from left to right:
not machine words, but really just a byte stream split into words to make
it easier to read. Thus, the last word may contain from one to four bytes.
The length of collected data is limited and can be less than the data length
- report in Data Length word.
-
-Here is an example of code to read the data stream in a well known programming
-language:
-
-class ParsedLine {
- int data_len; /* Available length of data */
- byte data[];
-
- void parseData(StringTokenizer st) {
- int availwords = st.countTokens();
- data = new byte[availwords * 4];
- data_len = 0;
- while (st.hasMoreTokens()) {
- 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);
- b = Integer.parseInt(
- data_str.substring(i*2, i*2 + 2),
- 16);
- if (b >= 128)
- b *= -1;
- data[data_len] = (byte) b;
- data_len++;
- }
- }
- }
-}
+ reported in the Data Length word. In the case of an Isochronous input (Zi)
+ completion where the received data is sparse in the buffer, the length of
+ the collected data can be greater than the Data Length value (because Data
+ Length counts only the bytes that were received whereas the Data words
+ contain the entire transfer buffer).
Examples: