On 11/07/2015 07:05 PM, Steinar H. Gunderson wrote:
Can you cat /sys/bus/usb/devices/2-2/power/usb3_hardware_lpm_u1
>and /sys/bus/usb/devices/2-2/power/usb3_hardware_lpm_u2 for several
>times? Don't use that device when cat these two files.
I waited a bit longer, and indeed, now it consistently shows enabled on both
cards.
klump:~> cat /sys/bus/usb/devices/2-1/power/usb3_hardware_lpm_u1
enabled
klump:~> cat /sys/bus/usb/devices/2-1/power/usb3_hardware_lpm_u2
enabled
klump:~> cat /sys/bus/usb/devices/2-2/power/usb3_hardware_lpm_u1
enabled
klump:~> cat /sys/bus/usb/devices/2-2/power/usb3_hardware_lpm_u2
enabled
That's good. Thank you for your time.
We've got below facts:
1. One card works well w/ or w/o LPM enabled.
2. Two cards work well w/o LPM, but not work w/ LPM. The error
is "not enough bus bandwidth".
We can come to a conclusion that "LPM consumes extra usb bus
bandwidth, this extra bandwidth could cause device not to work
due to limited bandwidth resources."
I have a patch attached in this email. It can disable LPM for any
devices during run time. Do you mind having a try? You can follow
below steps:
1) apply the attached two patches on top of the latest 4.3 kernel.
0001-usb-core-lpm-fix-usb3_hardware_lpm-sysfs-node.patch
0002-usb-core-lpm-add-sysfs-node-for-usb3-lpm-permit.patch
2) build and install the kernel.
3) boot your machine with the new kernel.
4) insert two Blackmagic Design device into USB3 root port.
5) disable LPM for devices in step 4).
# echo "0" > /sys/bus/usb/devices/<1st_device_path>/port/usb3_lpm_permit
# echo "0" > /sys/bus/usb/devices/<2nd_device_path>/port/usb3_lpm_permit
You can check your setting by reading the sysfs file. They should read 0.
6) start the two devices at the same time, can they work at the same time?
Thanks,
Baolu
For fun, I tried also with a USB 2.0 cable. U1 and U2 comes up as disabled,
but of course, the device doesn't work.
/* Steinar */
>From 836c0ab187bcc5a08ac3a6d55136203f922ad95b Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Date: Fri, 6 Nov 2015 09:53:59 +0800
Subject: [PATCH 2/3] 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.
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Zhuang Jin Can <jin.can.zhuang@xxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-usb | 11 ++++
drivers/usb/core/hub.c | 15 +++++-
drivers/usb/core/hub.h | 5 +-
drivers/usb/core/port.c | 89 ++++++++++++++++++++++++++++++++-
4 files changed, 116 insertions(+), 4 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 136ba17..4165c37 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -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@xxxxxxxxxxxxxxx>
+Description:
+ Some USB3.0 devices may not support usb3 lpm well. 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@xxxxxxxxxxxxxxx>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 94a10e0..023e39f 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4012,6 +4012,8 @@ 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 ||
@@ -4031,8 +4033,17 @@ 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);
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 688817f..45d070d 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -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);
}
-
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 2106183..cb18ce0 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -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))
--
2.1.4
>From c1c5a68c08ec669868e12d4d7bb48f24a2f36aab Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Date: Thu, 5 Nov 2015 14:08:48 +0800
Subject: [PATCH 1/3] 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.
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-usb | 16 +++++++++-------
Documentation/usb/power-management.txt | 11 ++++++-----
drivers/usb/core/hub.c | 29 +++++++++++++++++++++--------
drivers/usb/core/sysfs.c | 28 ++++++++++++++++++++++++----
include/linux/usb.h | 2 ++
5 files changed, 62 insertions(+), 24 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 3a4abfc..136ba17 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -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@xxxxxxxxxxxxxxx>
+ Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
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
diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index 4a15c90..0a94ffe 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
----------------------
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index bdeadc1..94a10e0 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3875,17 +3875,28 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
return;
}
- if (usb_set_lpm_timeout(udev, state, timeout))
+ ret = usb_set_lpm_timeout(udev, state, timeout);
+ if (ret) {
/* 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);
-
+ if (hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state))
+ dev_warn(&udev->dev,
+ "Could not disable xHCI %s timeout, "
+ "bus schedule bandwidth may be impacted.\n",
+ usb3_lpm_names[state]);
/* Only a configured device will accept the Set Feature U1/U2_ENABLE */
- else if (udev->actconfig)
+ } else if (udev->actconfig) {
usb_set_device_initiated_lpm(udev, state, true);
+ }
+ if (!ret) {
+ 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 +3936,12 @@ 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]);
+
+ 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 +3976,6 @@ 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 +4033,6 @@ 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);
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index d9ec2de..26a6a01 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -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 = {
diff --git a/include/linux/usb.h b/include/linux/usb.h
index b9a2807..211664f 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -584,6 +584,8 @@ 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 */
--
2.1.4
