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>

1 files changed, 6 insertions, 5 deletions

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
         ----------------------