diff options
| author | Jon Flatley <jflat@chromium.org> | 2018-09-20 19:17:54 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-28 15:08:17 +0200 |
| commit | 201af55da8a3986297d7c3493f839dfc96ffd7db (patch) | |
| tree | 06e3cdd663ed2f0918ea552c2ea7f22ba599a857 /Documentation | |
| parent | usb: typec: fusb302: Resolve fixed power role contract setup (diff) | |
| download | linux-201af55da8a3986297d7c3493f839dfc96ffd7db.tar.xz linux-201af55da8a3986297d7c3493f839dfc96ffd7db.zip | |
usb: core: added uevent for over-current
After commit 1cbd53c8cd85 ("usb: core: introduce per-port over-current
counters") usb ports expose a sysfs value 'over_current_count'
to user space. This value on its own is not very useful as it requires
manual polling.
As a solution, fire a udev event from the usb hub device that specifies
the values 'OVER_CURRENT_PORT' and 'OVER_CURRENT_COUNT' that indicate
the path of the usb port where the over-current event occurred and the
value of 'over_current_count' in sysfs. Additionally, call
sysfs_notify() so the sysfs value supports poll().
Signed-off-by: Jon Flatley <jflat@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 08d456e07b53..c4a70f532ec3 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -219,7 +219,14 @@ Description: ports and report them to the kernel. This attribute is to expose the number of over-current situation occurred on a specific port to user space. This file will contain an unsigned 32 bit value - which wraps to 0 after its maximum is reached. + which wraps to 0 after its maximum is reached. This file supports + poll() for monitoring changes to this value in user space. + + Any time this value changes the corresponding hub device will send a + udev event with the following attributes: + + OVER_CURRENT_PORT=/sys/bus/usb/devices/.../(hub interface)/portX + OVER_CURRENT_COUNT=[current value of this sysfs attribute] What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit Date: November 2015 |