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authorWolfgang Wiedmeyer <wolfgit@wiedmeyer.de>2015-10-23 03:29:33 +0200
committerWolfgang Wiedmeyer <wolfgit@wiedmeyer.de>2015-10-23 03:29:33 +0200
commit15dfd0df63ce6847081d09b2bbd567cc0cc4eae1 (patch)
tree3b73f24fcef970bfcace3cbb297cfa57f3994682 /Documentation/ABI/testing/sysfs-module
parent328aa7a45af61bc0060c80847daa67fef7b9c0d0 (diff)
parent0149138c4142da287d23f9d5c6038f7fb5e30ac2 (diff)
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initial merge with 3.2.72
Diffstat (limited to 'Documentation/ABI/testing/sysfs-module')
-rw-r--r--Documentation/ABI/testing/sysfs-module23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-module b/Documentation/ABI/testing/sysfs-module
index cfcec3b..9489ea8 100644
--- a/Documentation/ABI/testing/sysfs-module
+++ b/Documentation/ABI/testing/sysfs-module
@@ -10,3 +10,26 @@ KernelVersion: 2.6.35
Contact: masa-korg@dsn.okisemi.com
Description: Write/read Option ROM data.
+
+What: /sys/module/ehci_hcd/drivers/.../uframe_periodic_max
+Date: July 2011
+KernelVersion: 3.1
+Contact: Kirill Smelkov <kirr@mns.spb.ru>
+Description: Maximum time allowed for periodic transfers per microframe (μs)
+
+ [ USB 2.0 sets maximum allowed time for periodic transfers per
+ microframe to be 80%, that is 100 microseconds out of 125
+ microseconds (full microframe).
+
+ However there are cases, when 80% max isochronous bandwidth is
+ too limiting. For example two video streams could require 110
+ microseconds of isochronous bandwidth per microframe to work
+ together. ]
+
+ Through this setting it is possible to raise the limit so that
+ the host controller would allow allocating more than 100
+ microseconds of periodic bandwidth per microframe.
+
+ Beware, non-standard modes are usually not thoroughly tested by
+ hardware designers, and the hardware can malfunction when this
+ setting differ from default 100.