Commit 355c74e5 authored by Bjørn Mork's avatar Bjørn Mork Committed by Greg Kroah-Hartman
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usb: export firmware port location in sysfs 



The platform firmware "location" data is used to find port peer
relationships. But firmware is an unreliable source, and there are
real world examples of errors leading to missing or wrong peer
relationships.  Debugging this is currently hard.

Exporting the location attribute makes it easier to spot mismatches
between the firmware data and the real world.

Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bd0e6c96

Documentation/ABI/testing/sysfs-bus-usb

+10 −0
Original line number Diff line number Diff line
@@ -189,6 +189,16 @@ 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/location

Date:		October 2018

Contact:	Bjørn Mork <bjorn@mork.no>

Description:

		Some platforms provide usb port physical location through

		firmware. This is used by the kernel to pair up logical ports

		mapping to the same physical connector. The attribute exposes the

		raw location value as a hex integer.





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

Date:		May 2018

Contact:	Nicolas Boichat <drinkcat@chromium.org>

drivers/usb/core/port.c

+10 −0
Original line number Diff line number Diff line
@@ -16,6 +16,15 @@ static int usb_port_block_power_off; 


static const struct attribute_group *port_dev_group[];



static ssize_t location_show(struct device *dev,

			     struct device_attribute *attr, char *buf)

{

	struct usb_port *port_dev = to_usb_port(dev);



	return sprintf(buf, "0x%08x\n", port_dev->location);

}

static DEVICE_ATTR_RO(location);



static ssize_t connect_type_show(struct device *dev,

				 struct device_attribute *attr, char *buf)

{
@@ -140,6 +149,7 @@ static DEVICE_ATTR_RW(usb3_lpm_permit); 


static struct attribute *port_dev_attrs[] = {

	&dev_attr_connect_type.attr,

	&dev_attr_location.attr,

	&dev_attr_quirks.attr,

	&dev_attr_over_current_count.attr,

	NULL,

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