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authorLu Baolu <baolu.lu@linux.intel.com>2015-11-14 16:26:32 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-12-01 14:58:18 -0800
commitbf5ce5bf3cc7136fd7fe5e8999a580bc93a9c8f6 (patch)
treeceba9f149feb24ad8cb93bb33a2655dd59e32df8 /Documentation
parentc56a2b2bc661fe089fde9beffeadcb0ecb5e934b (diff)
downloadlinux-bf5ce5bf3cc7136fd7fe5e8999a580bc93a9c8f6.tar.bz2
usb: core: lpm: fix usb3_hardware_lpm sysfs node
Commit 655fe4effe0f ("usbcore: add sysfs support to xHCI usb3 hardware LPM") introduced usb3_hardware_lpm sysfs node. This doesn't show the correct status of USB3 U1 and U2 LPM status. This patch fixes this by replacing usb3_hardware_lpm with two nodes, usb3_hardware_lpm_u1 (for U1) and usb3_hardware_lpm_u2 (for U2), and recording the U1/U2 LPM status in right places. This patch should be back-ported to kernels as old as 4.3, that contains Commit 655fe4effe0f ("usbcore: add sysfs support to xHCI usb3 hardware LPM"). Cc: stable@vger.kernel.org Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-usb16
-rw-r--r--Documentation/usb/power-management.txt11
2 files changed, 15 insertions, 12 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 3a4abfc44f5e..136ba17d2da0 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -134,19 +134,21 @@ Description:
enabled for the device. Developer can write y/Y/1 or n/N/0 to
the file to enable/disable the feature.
-What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm
-Date: June 2015
+What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1
+ /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2
+Date: November 2015
Contact: Kevin Strasser <kevin.strasser@linux.intel.com>
+ Lu Baolu <baolu.lu@linux.intel.com>
Description:
If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged
in to a xHCI host which supports link PM, it will check if U1
and U2 exit latencies have been set in the BOS descriptor; if
- the check is is passed and the host supports USB3 hardware LPM,
+ the check is passed and the host supports USB3 hardware LPM,
USB3 hardware LPM will be enabled for the device and the USB
- device directory will contain a file named
- power/usb3_hardware_lpm. The file holds a string value (enable
- or disable) indicating whether or not USB3 hardware LPM is
- enabled for the device.
+ device directory will contain two files named
+ power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These
+ files hold a string value (enable or disable) indicating whether
+ or not USB3 hardware LPM U1 or U2 is enabled for the device.
What: /sys/bus/usb/devices/.../removable
Date: February 2012
diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index 4a15c90bc11d..0a94ffe17ab6 100644
--- a/Documentation/usb/power-management.txt
+++ b/Documentation/usb/power-management.txt
@@ -537,17 +537,18 @@ relevant attribute files are usb2_hardware_lpm and usb3_hardware_lpm.
can write y/Y/1 or n/N/0 to the file to enable/disable
USB2 hardware LPM manually. This is for test purpose mainly.
- power/usb3_hardware_lpm
+ power/usb3_hardware_lpm_u1
+ power/usb3_hardware_lpm_u2
When a USB 3.0 lpm-capable device is plugged in to a
xHCI host which supports link PM, it will check if U1
and U2 exit latencies have been set in the BOS
descriptor; if the check is is passed and the host
supports USB3 hardware LPM, USB3 hardware LPM will be
- enabled for the device and this file will be created.
- The file holds a string value (enable or disable)
- indicating whether or not USB3 hardware LPM is
- enabled for the device.
+ enabled for the device and these files will be created.
+ The files hold a string value (enable or disable)
+ indicating whether or not USB3 hardware LPM U1 or U2
+ is enabled for the device.
USB Port Power Control
----------------------