Commit 513072d9 authored by Lu Baolu's avatar Lu Baolu Committed by Greg Kroah-Hartman
Browse files

usb: core: lpm: add sysfs node for usb3 lpm permit 



USB3 LPM is default on in Linux kernel if both xHCI host controller
and the USB devices declare to be LPM-capable. Unfortunately, some
devices are known to work well with LPM disabled, but to be broken
if LPM is enabled, although it declares the LPM capability.  Users
won't be able to use this kind of devices, until someone puts them
in the kernel blacklist and gets the kernel upgraded.

This patch adds a sysfs node to permit or forbit USB3 LPM U1 or U2
entry for a port. The settings apply to both before and after device
enumeration. Supported values are "0" - neither u1 nor u2 permitted,
"u1" - only u1 is permitted, "u2" - only u2 is permitted, "u1_u2" -
both u1 and u2 are permitted. With this interface, users can use an
LPM-unfriendly USB device on a released Linux kernel.

Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: default avatarZhuang Jin Can <jin.can.zhuang@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bf5ce5bf

Documentation/ABI/testing/sysfs-bus-usb

+11 −0
Original line number Diff line number Diff line
@@ -189,6 +189,17 @@ Description: 
		The file will read "hotplug", "wired" and "not used" if the

		information is available, and "unknown" otherwise.



What:		/sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit

Date:		November 2015

Contact:	Lu Baolu <baolu.lu@linux.intel.com>

Description:

		Some USB3.0 devices are not friendly to USB3 LPM.  usb3_lpm_permit

		attribute allows enabling/disabling usb3 lpm of a port. It takes

		effect both before and after a usb device is enumerated. Supported

		values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1

		is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and

		u2 are permitted.



What:		/sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout

Date:		May 2013

Contact:	Mathias Nyman <mathias.nyman@linux.intel.com>

drivers/usb/core/hub.c

+13 −2
Original line number Diff line number Diff line
@@ -4020,6 +4020,8 @@ EXPORT_SYMBOL_GPL(usb_unlocked_disable_lpm); 
void usb_enable_lpm(struct usb_device *udev)

{

	struct usb_hcd *hcd;

	struct usb_hub *hub;

	struct usb_port *port_dev;



	if (!udev || !udev->parent ||

			udev->speed != USB_SPEED_SUPER ||
@@ -4039,7 +4041,16 @@ void usb_enable_lpm(struct usb_device *udev) 
	if (udev->lpm_disable_count > 0)

		return;



	hub = usb_hub_to_struct_hub(udev->parent);

	if (!hub)

		return;



	port_dev = hub->ports[udev->portnum - 1];



	if (port_dev->usb3_lpm_u1_permit)

		usb_enable_link_state(hcd, udev, USB3_LPM_U1);



	if (port_dev->usb3_lpm_u2_permit)

		usb_enable_link_state(hcd, udev, USB3_LPM_U2);

}

EXPORT_SYMBOL_GPL(usb_enable_lpm);

drivers/usb/core/hub.h

+4 −1
Original line number Diff line number Diff line
@@ -92,6 +92,8 @@ struct usb_hub { 
 * @status_lock: synchronize port_event() vs usb_port_{suspend|resume}

 * @portnum: port index num based one

 * @is_superspeed cache super-speed status

 * @usb3_lpm_u1_permit: whether USB3 U1 LPM is permitted.

 * @usb3_lpm_u2_permit: whether USB3 U2 LPM is permitted.

 */

struct usb_port {

	struct usb_device *child;
@@ -104,6 +106,8 @@ struct usb_port { 
	struct mutex status_lock;

	u8 portnum;

	unsigned int is_superspeed:1;

	unsigned int usb3_lpm_u1_permit:1;

	unsigned int usb3_lpm_u2_permit:1;

};



#define to_usb_port(_dev) \
@@ -155,4 +159,3 @@ static inline int hub_port_debounce_be_stable(struct usb_hub *hub, 
{

	return hub_port_debounce(hub, port1, false);

}

drivers/usb/core/port.c

+88 −1
Original line number Diff line number Diff line
@@ -50,6 +50,72 @@ static ssize_t connect_type_show(struct device *dev, 
}

static DEVICE_ATTR_RO(connect_type);



static ssize_t usb3_lpm_permit_show(struct device *dev,

			      struct device_attribute *attr, char *buf)

{

	struct usb_port *port_dev = to_usb_port(dev);

	const char *p;



	if (port_dev->usb3_lpm_u1_permit) {

		if (port_dev->usb3_lpm_u2_permit)

			p = "u1_u2";

		else

			p = "u1";

	} else {

		if (port_dev->usb3_lpm_u2_permit)

			p = "u2";

		else

			p = "0";

	}



	return sprintf(buf, "%s\n", p);

}



static ssize_t usb3_lpm_permit_store(struct device *dev,

			       struct device_attribute *attr,

			       const char *buf, size_t count)

{

	struct usb_port *port_dev = to_usb_port(dev);

	struct usb_device *udev = port_dev->child;

	struct usb_hcd *hcd;



	if (!strncmp(buf, "u1_u2", 5)) {

		port_dev->usb3_lpm_u1_permit = 1;

		port_dev->usb3_lpm_u2_permit = 1;



	} else if (!strncmp(buf, "u1", 2)) {

		port_dev->usb3_lpm_u1_permit = 1;

		port_dev->usb3_lpm_u2_permit = 0;



	} else if (!strncmp(buf, "u2", 2)) {

		port_dev->usb3_lpm_u1_permit = 0;

		port_dev->usb3_lpm_u2_permit = 1;



	} else if (!strncmp(buf, "0", 1)) {

		port_dev->usb3_lpm_u1_permit = 0;

		port_dev->usb3_lpm_u2_permit = 0;

	} else

		return -EINVAL;



	/* If device is connected to the port, disable or enable lpm

	 * to make new u1 u2 setting take effect immediately.

	 */

	if (udev) {

		hcd = bus_to_hcd(udev->bus);

		if (!hcd)

			return -EINVAL;

		usb_lock_device(udev);

		mutex_lock(hcd->bandwidth_mutex);

		if (!usb_disable_lpm(udev))

			usb_enable_lpm(udev);

		mutex_unlock(hcd->bandwidth_mutex);

		usb_unlock_device(udev);

	}



	return count;

}

static DEVICE_ATTR_RW(usb3_lpm_permit);



static struct attribute *port_dev_attrs[] = {

	&dev_attr_connect_type.attr,

	NULL,
@@ -64,6 +130,21 @@ static const struct attribute_group *port_dev_group[] = { 
	NULL,

};



static struct attribute *port_dev_usb3_attrs[] = {

	&dev_attr_usb3_lpm_permit.attr,

	NULL,

};



static struct attribute_group port_dev_usb3_attr_grp = {

	.attrs = port_dev_usb3_attrs,

};



static const struct attribute_group *port_dev_usb3_group[] = {

	&port_dev_attr_grp,

	&port_dev_usb3_attr_grp,

	NULL,

};



static void usb_port_device_release(struct device *dev)

{

	struct usb_port *port_dev = to_usb_port(dev);
@@ -401,6 +482,7 @@ static void find_and_link_peer(struct usb_hub *hub, int port1) 
int usb_hub_create_port_device(struct usb_hub *hub, int port1)

{

	struct usb_port *port_dev;

	struct usb_device *hdev = hub->hdev;

	int retval;



	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
@@ -417,6 +499,11 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1) 
	port_dev->portnum = port1;

	set_bit(port1, hub->power_bits);

	port_dev->dev.parent = hub->intfdev;

	if (hub_is_superspeed(hdev)) {

		port_dev->usb3_lpm_u1_permit = 1;

		port_dev->usb3_lpm_u2_permit = 1;

		port_dev->dev.groups = port_dev_usb3_group;

	} else

		port_dev->dev.groups = port_dev_group;

	port_dev->dev.type = &usb_port_device_type;

	port_dev->dev.driver = &usb_port_driver;

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