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

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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: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Zhuang Jin Can <jin.can.zhuang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lu Baolu 2015-11-14 16:26:33 +08:00 committed by Greg Kroah-Hartman
parent bf5ce5bf3c
commit 513072d90a
4 changed files with 116 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
Documentation/ABI/testing/sysfs-bus-usb
View File

@ -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>

15
drivers/usb/core/hub.c
View File

@ -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 ||
@ -4039,8 +4041,17 @@ void usb_enable_lpm(struct usb_device *udev)
if (udev->lpm_disable_count > 0)
return;
usb_enable_link_state(hcd, udev, USB3_LPM_U1);
usb_enable_link_state(hcd, udev, USB3_LPM_U2);
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);

5
drivers/usb/core/hub.h
View File

@ -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);
}

89
drivers/usb/core/port.c
View File

@ -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);
@ -417,7 +499,12 @@ 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;
port_dev->dev.groups = port_dev_group;
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;
if (hub_is_superspeed(hub->hdev))