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usb: core: lpm: fix usb3_hardware_lpm sysfs node

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Commit 655fe4effe ("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 655fe4effe ("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>
This commit is contained in:
Lu Baolu
2015-11-14 16:26:32 +08:00
committed by Greg Kroah-Hartman
parent c56a2b2bc6
commit bf5ce5bf3c
5 changed files with 75 additions and 26 deletions
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11
Documentation/usb/power-management.txt
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@@ -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
----------------------