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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-03-25 17:41:20 +0200
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-03-25 17:41:20 +0200
commit7bf7e370d5919112c223a269462cd0b546903829 (patch)
tree03ccc715239df14ae168277dbccc9d9cf4d8a2c8 /Documentation/usb/usbmon.txt
parent68b1a1e786f29c900fa1c516a402e24f0ece622a (diff)
parentd39dd11c3e6a7af5c20bfac40594db36cf270f42 (diff)
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6: (9356 commits) [media] rc: update for bitop name changes fs: simplify iget & friends fs: pull inode->i_lock up out of writeback_single_inode fs: rename inode_lock to inode_hash_lock fs: move i_wb_list out from under inode_lock fs: move i_sb_list out from under inode_lock fs: remove inode_lock from iput_final and prune_icache fs: Lock the inode LRU list separately fs: factor inode disposal fs: protect inode->i_state with inode->i_lock lib, arch: add filter argument to show_mem and fix private implementations SLUB: Write to per cpu data when allocating it slub: Fix debugobjects with lockless fastpath autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd() autofs4 - remove autofs4_lock autofs4 - fix d_manage() return on rcu-walk autofs4 - fix autofs4_expire_indirect() traversal autofs4 - fix dentry leak in autofs4_expire_direct() autofs4 - reinstate last used update on access vfs - check non-mountpoint dentry might block in __follow_mount_rcu() ... NOTE! This merge commit was created to fix compilation error. The block tree was merged upstream and removed the 'elv_queue_empty()' function which the new 'mtdswap' driver is using. So a simple merge of the mtd tree with upstream does not compile. And the mtd tree has already be published, so re-basing it is not an option. To fix this unfortunate situation, I had to merge upstream into the mtd-2.6.git tree without committing, put the fixup patch on top of this, and then commit this. The result is that we do not have commits which do not compile. In other words, this merge commit "merges" 3 things: the MTD tree, the upstream tree, and the fixup patch.
Diffstat (limited to 'Documentation/usb/usbmon.txt')
-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 66f92d1194c1..a4efa0462f05 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: