diff options
author | Roy Luo <royluo@google.com> | 2023-06-08 01:59:12 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-06-13 11:58:26 +0200 |
commit | 83cb2604f641cecadc275ca18adbba4bf262320f (patch) | |
tree | 1cae3704f2f1385b02827ab2721f30c2c08d5776 /drivers/usb/core/hub.h | |
parent | edd60d24bd858cef165274e4cd6cab43bdc58d15 (diff) |
usb: core: add sysfs entry for usb device state
Expose usb device state to userland as the information is useful in
detecting non-compliant setups and diagnosing enumeration failures.
For example:
- End-to-end signal integrity issues: the device would fail port reset
repeatedly and thus be stuck in POWERED state.
- Charge-only cables (missing D+/D- lines): the device would never enter
POWERED state as the HC would not see any pullup.
What's the status quo?
We do have error logs such as "Cannot enable. Maybe the USB cable is bad?"
to flag potential setup issues, but there's no good way to expose them to
userspace.
Why add a sysfs entry in struct usb_port instead of struct usb_device?
The struct usb_device is not device_add() to the system until it's in
ADDRESS state hence we would miss the first two states. The struct
usb_port is a better place to keep the information because its life
cycle is longer than the struct usb_device that is attached to the port.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202306042228.e532af6e-oliver.sang@intel.com
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Roy Luo <royluo@google.com>
Message-ID: <20230608015913.1679984-1-royluo@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/hub.h')
-rw-r--r-- | drivers/usb/core/hub.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index e23833562e4f..37897afd1b64 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -84,6 +84,8 @@ struct usb_hub { * @peer: related usb2 and usb3 ports (share the same connector) * @req: default pm qos request for hubs without port power control * @connect_type: port's connect type + * @state: device state of the usb device attached to the port + * @state_kn: kernfs_node of the sysfs attribute that accesses @state * @location: opaque representation of platform connector location * @status_lock: synchronize port_event() vs usb_port_{suspend|resume} * @portnum: port index num based one @@ -100,6 +102,8 @@ struct usb_port { struct usb_port *peer; struct dev_pm_qos_request *req; enum usb_port_connect_type connect_type; + enum usb_device_state state; + struct kernfs_node *state_kn; usb_port_location_t location; struct mutex status_lock; u32 over_current_count; |