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usb: core: lpm: fix usb3_hardware_lpm sysfs node 

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
Documentation/ABI/testing/sysfs-bus-usb
View File

@ -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

11
Documentation/usb/power-management.txt
View File

@ -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
----------------------

39
drivers/usb/core/hub.c
View File

@ -3875,17 +3875,30 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
return;
}
if (usb_set_lpm_timeout(udev, state, timeout))
if (usb_set_lpm_timeout(udev, state, timeout)) {
/* If we can't set the parent hub U1/U2 timeout,
* device-initiated LPM won't be allowed either, so let the xHCI
* host know that this link state won't be enabled.
*/
hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state);
} else {
/* Only a configured device will accept the Set Feature
* U1/U2_ENABLE
*/
if (udev->actconfig)
usb_set_device_initiated_lpm(udev, state, true);
/* Only a configured device will accept the Set Feature U1/U2_ENABLE */
else if (udev->actconfig)
usb_set_device_initiated_lpm(udev, state, true);
/* As soon as usb_set_lpm_timeout(timeout) returns 0, the
* hub-initiated LPM is enabled. Thus, LPM is enabled no
* matter the result of usb_set_device_initiated_lpm().
* The only difference is whether device is able to initiate
* LPM.
*/
if (state == USB3_LPM_U1)
udev->usb3_lpm_u1_enabled = 1;
else if (state == USB3_LPM_U2)
udev->usb3_lpm_u2_enabled = 1;
}
}
/*
@ -3925,6 +3938,18 @@ static int usb_disable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
dev_warn(&udev->dev, "Could not disable xHCI %s timeout, "
"bus schedule bandwidth may be impacted.\n",
usb3_lpm_names[state]);
/* As soon as usb_set_lpm_timeout(0) return 0, hub initiated LPM
* is disabled. Hub will disallows link to enter U1/U2 as well,
* even device is initiating LPM. Hence LPM is disabled if hub LPM
* timeout set to 0, no matter device-initiated LPM is disabled or
* not.
*/
if (state == USB3_LPM_U1)
udev->usb3_lpm_u1_enabled = 0;
else if (state == USB3_LPM_U2)
udev->usb3_lpm_u2_enabled = 0;
return 0;
}
@ -3959,8 +3984,6 @@ int usb_disable_lpm(struct usb_device *udev)
if (usb_disable_link_state(hcd, udev, USB3_LPM_U2))
goto enable_lpm;
udev->usb3_lpm_enabled = 0;
return 0;
enable_lpm:
@ -4018,8 +4041,6 @@ void usb_enable_lpm(struct usb_device *udev)
usb_enable_link_state(hcd, udev, USB3_LPM_U1);
usb_enable_link_state(hcd, udev, USB3_LPM_U2);
udev->usb3_lpm_enabled = 1;
}
EXPORT_SYMBOL_GPL(usb_enable_lpm);

31
drivers/usb/core/sysfs.c
View File

@ -531,7 +531,7 @@ static ssize_t usb2_lpm_besl_store(struct device *dev,
}
static DEVICE_ATTR_RW(usb2_lpm_besl);
static ssize_t usb3_hardware_lpm_show(struct device *dev,
static ssize_t usb3_hardware_lpm_u1_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usb_device *udev = to_usb_device(dev);
@ -539,7 +539,7 @@ static ssize_t usb3_hardware_lpm_show(struct device *dev,
usb_lock_device(udev);
if (udev->usb3_lpm_enabled)
if (udev->usb3_lpm_u1_enabled)
p = "enabled";
else
p = "disabled";
@ -548,7 +548,26 @@ static ssize_t usb3_hardware_lpm_show(struct device *dev,
return sprintf(buf, "%s\n", p);
}
static DEVICE_ATTR_RO(usb3_hardware_lpm);
static DEVICE_ATTR_RO(usb3_hardware_lpm_u1);
static ssize_t usb3_hardware_lpm_u2_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usb_device *udev = to_usb_device(dev);
const char *p;
usb_lock_device(udev);
if (udev->usb3_lpm_u2_enabled)
p = "enabled";
else
p = "disabled";
usb_unlock_device(udev);
return sprintf(buf, "%s\n", p);
}
static DEVICE_ATTR_RO(usb3_hardware_lpm_u2);
static struct attribute *usb2_hardware_lpm_attr[] = {
&dev_attr_usb2_hardware_lpm.attr,
@ -562,7 +581,8 @@ static struct attribute_group usb2_hardware_lpm_attr_group = {
};
static struct attribute *usb3_hardware_lpm_attr[] = {
&dev_attr_usb3_hardware_lpm.attr,
&dev_attr_usb3_hardware_lpm_u1.attr,
&dev_attr_usb3_hardware_lpm_u2.attr,
NULL,
};
static struct attribute_group usb3_hardware_lpm_attr_group = {
@ -592,7 +612,8 @@ static int add_power_attributes(struct device *dev)
if (udev->usb2_hw_lpm_capable == 1)
rc = sysfs_merge_group(&dev->kobj,
&usb2_hardware_lpm_attr_group);
if (udev->lpm_capable == 1)
if (udev->speed == USB_SPEED_SUPER &&
udev->lpm_capable == 1)
rc = sysfs_merge_group(&dev->kobj,
&usb3_hardware_lpm_attr_group);
}

4
include/linux/usb.h
View File

@ -511,6 +511,8 @@ struct usb3_lpm_parameters {
* @usb2_hw_lpm_enabled: USB2 hardware LPM is enabled
* @usb2_hw_lpm_allowed: Userspace allows USB 2.0 LPM to be enabled
* @usb3_lpm_enabled: USB3 hardware LPM enabled
* @usb3_lpm_u1_enabled: USB3 hardware U1 LPM enabled
* @usb3_lpm_u2_enabled: USB3 hardware U2 LPM enabled
* @string_langid: language ID for strings
* @product: iProduct string, if present (static)
* @manufacturer: iManufacturer string, if present (static)
@ -584,6 +586,8 @@ struct usb_device {
unsigned usb2_hw_lpm_enabled:1;
unsigned usb2_hw_lpm_allowed:1;
unsigned usb3_lpm_enabled:1;
unsigned usb3_lpm_u1_enabled:1;
unsigned usb3_lpm_u2_enabled:1;
int string_langid;
/* static strings from the device */