From 25244227158e1502062041365a439a54cb8fe673 Mon Sep 17 00:00:00 2001 From: Nicolas Boichat Date: Mon, 28 May 2018 14:32:18 +0800 Subject: usb: hub: Per-port setting to use old enumeration scheme 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 Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/usb.h') diff --git a/include/linux/usb.h b/include/linux/usb.h index beffceec4915..2ade17992ed6 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -489,6 +489,13 @@ enum usb_port_connect_type { USB_PORT_NOT_USED, }; +/* + * USB port quirks. + */ + +/* For the given port, prefer the old (faster) enumeration scheme. */ +#define USB_PORT_QUIRK_OLD_SCHEME BIT(0) + /* * USB 2.0 Link Power Management (LPM) parameters. */ -- cgit v1.2.3-70-g09d2