xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

usb: hub: Per-port setting to use old enumeration scheme

Browse Source 
The "old" enumeration scheme is considerably faster (it takes
~244ms instead of ~356ms to get the descriptor).

It is currently only possible to use the old scheme globally
(/sys/module/usbcore/parameters/old_scheme_first), which is not
desirable as the new scheme was introduced to increase compatibility
with more devices.

However, in our case, we care about time-to-active for a specific
USB device (which we make the firmware for), on a specific port
(that is pogo-pin based: not a standard USB port). This new
sysfs option makes it possible to use the old scheme on a single
port only.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicolas Boichat
2018-05-28 14:32:18 +08:00
committed by Greg Kroah-Hartman
parent 380375b937
commit 2524422715
5 changed files with 58 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/usb/core/hub.c
View File

@@ -2636,7 +2636,7 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
#define SET_ADDRESS_TRIES 2
#define GET_DESCRIPTOR_TRIES 2
#define SET_CONFIG_TRIES (2 * (use_both_schemes + 1))
#define USE_NEW_SCHEME(i) ((i) / 2 == (int)old_scheme_first)
#define USE_NEW_SCHEME(i, scheme) ((i) / 2 == (int)scheme)
#define HUB_ROOT_RESET_TIME 60 /* times are in msec */
#define HUB_SHORT_RESET_TIME 10
@@ -2651,12 +2651,16 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
* enumeration failures, so disable this enumeration scheme for USB3
* devices.
*/
static bool use_new_scheme(struct usb_device *udev, int retry)
static bool use_new_scheme(struct usb_device *udev, int retry,
struct usb_port *port_dev)
{
int old_scheme_first_port =
port_dev->quirks & USB_PORT_QUIRK_OLD_SCHEME;
if (udev->speed >= USB_SPEED_SUPER)
return false;
return USE_NEW_SCHEME(retry);
return USE_NEW_SCHEME(retry, old_scheme_first_port || old_scheme_first);
}
/* Is a USB 3.0 port in the Inactive or Compliance Mode state?
@@ -4392,6 +4396,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
{
struct usb_device *hdev = hub->hdev;
struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
struct usb_port *port_dev = hub->ports[port1 - 1];
int retries, operations, retval, i;
unsigned delay = HUB_SHORT_RESET_TIME;
enum usb_device_speed oldspeed = udev->speed;
@@ -4513,7 +4518,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
for (retries = 0; retries < GET_DESCRIPTOR_TRIES; (++retries, msleep(100))) {
bool did_new_scheme = false;
if (use_new_scheme(udev, retry_counter)) {
if (use_new_scheme(udev, retry_counter, port_dev)) {
struct usb_device_descriptor *buf;
int r = 0;

1
drivers/usb/core/hub.h
View File

@@ -98,6 +98,7 @@ struct usb_port {
struct mutex status_lock;
u32 over_current_count;
u8 portnum;
u32 quirks;
unsigned int is_superspeed:1;
unsigned int usb3_lpm_u1_permit:1;
unsigned int usb3_lpm_u2_permit:1;

23
drivers/usb/core/port.c
View File

@@ -50,6 +50,28 @@ static ssize_t over_current_count_show(struct device *dev,
}
static DEVICE_ATTR_RO(over_current_count);
static ssize_t quirks_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usb_port *port_dev = to_usb_port(dev);
return sprintf(buf, "%08x\n", port_dev->quirks);
}
static ssize_t quirks_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct usb_port *port_dev = to_usb_port(dev);
u32 value;
if (kstrtou32(buf, 16, &value))
return -EINVAL;
port_dev->quirks = value;
return count;
}
static DEVICE_ATTR_RW(quirks);
static ssize_t usb3_lpm_permit_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -118,6 +140,7 @@ static DEVICE_ATTR_RW(usb3_lpm_permit);
static struct attribute *port_dev_attrs[] = {
&dev_attr_connect_type.attr,
&dev_attr_quirks.attr,
&dev_attr_over_current_count.attr,
NULL,
};