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Commit 4750bc78 authored by Thang Q. Nguyen's avatar Thang Q. Nguyen Committed by Greg Kroah-Hartman
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usb: host: xhci support option to disable the xHCI USB2 HW LPM 



XHCI specification 1.1 does not require xHCI-compliant controllers
to always enable hardware USB2 LPM. However, the current xHCI
driver always enable it when seeing HLC=1.
This patch supports an option for users to control disabling
USB2 Hardware LPM via DT/ACPI attribute.
This option is needed in case user would like to disable this
feature. For example, their xHCI controller has its USB2 HW LPM
broken.

Signed-off-by: default avatarTung Nguyen <tunguyen@apm.com>
Signed-off-by: default avatarThang Q. Nguyen <tqnguyen@apm.com>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fb9bbce6

Documentation/devicetree/bindings/usb/usb-xhci.txt

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ Required properties: 


Optional properties:

  - clocks: reference to a clock

  - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM

  - usb3-lpm-capable: determines if platform is USB3 LPM capable

  - quirk-broken-port-ped: set if the controller has broken port disable mechanism

drivers/usb/host/xhci-plat.c

+3 −0
Original line number Diff line number Diff line
@@ -259,6 +259,9 @@ static int xhci_plat_probe(struct platform_device *pdev) 
		goto disable_clk;

	}



	if (device_property_read_bool(sysdev, "usb2-lpm-disable"))

		xhci->quirks |= XHCI_HW_LPM_DISABLE;



	if (device_property_read_bool(sysdev, "usb3-lpm-capable"))

		xhci->quirks |= XHCI_LPM_SUPPORT;

drivers/usb/host/xhci.c

+1 −1
Original line number Diff line number Diff line
@@ -4087,7 +4087,7 @@ static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, 
	xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",

			enable ? "enable" : "disable", port_num + 1);



	if (enable) {

	if (enable && !(xhci->quirks & XHCI_HW_LPM_DISABLE)) {

		/* Host supports BESL timeout instead of HIRD */

		if (udev->usb2_hw_lpm_besl_capable) {

			/* if device doesn't have a preferred BESL value use a

drivers/usb/host/xhci.h

+1 −0
Original line number Diff line number Diff line
@@ -1828,6 +1828,7 @@ struct xhci_hcd { 
#define XHCI_LIMIT_ENDPOINT_INTERVAL_7	(1 << 26)

#define XHCI_U2_DISABLE_WAKE	(1 << 27)

#define XHCI_ASMEDIA_MODIFY_FLOWCONTROL	(1 << 28)

#define XHCI_HW_LPM_DISABLE	(1 << 29)



	unsigned int		num_active_eps;

	unsigned int		limit_active_eps;