Commit 424140d3 authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
Browse files

xhci: prevent U2 link power state if Intel tier policy prevented U1 



Don't enable U1 or U2 Link powermanagenet (LPM) states for USB3
devices connected to tier 2 or further hubs.

For unknown reasons we previously only prevented U1.
Be consistent, and prevent both U1/U2 states if tier policy doesn't
allow LPM.

Also check the tier policy a bit earlier, and return if U1/U2 is
not allowed. This avoids unnecessary xhci MEL commands.

Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220511220450.85367-8-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 25355e04

drivers/usb/host/xhci.c

+4 −7
Original line number Diff line number Diff line
@@ -4888,9 +4888,6 @@ static int xhci_check_intel_tier_policy(struct usb_device *udev, 
	struct usb_device *parent;

	unsigned int num_hubs;



	if (state == USB3_LPM_U2)

		return 0;



	/* Don't enable U1 if the device is on a 2nd tier hub or lower. */

	for (parent = udev->parent, num_hubs = 0; parent->parent;

			parent = parent->parent)
@@ -4899,7 +4896,7 @@ static int xhci_check_intel_tier_policy(struct usb_device *udev, 
	if (num_hubs < 2)

		return 0;



	dev_dbg(&udev->dev, "Disabling U1 link state for device"

	dev_dbg(&udev->dev, "Disabling U1/U2 link state for device"

			" below second-tier hub.\n");

	dev_dbg(&udev->dev, "Plug device into first-tier hub "

			"to decrease power consumption.\n");
@@ -4940,9 +4937,6 @@ static u16 xhci_calculate_lpm_timeout(struct usb_hcd *hcd, 
		return timeout;

	}



	if (xhci_check_tier_policy(xhci, udev, state) < 0)

		return timeout;



	/* Gather some information about the currently installed configuration

	 * and alternate interface settings.

	 */
@@ -5049,6 +5043,9 @@ static int xhci_enable_usb3_lpm_timeout(struct usb_hcd *hcd, 
			!xhci->devs[udev->slot_id])

		return USB3_LPM_DISABLED;



	if (xhci_check_tier_policy(xhci, udev, state) < 0)

		return USB3_LPM_DISABLED;



	hub_encoded_timeout = xhci_calculate_lpm_timeout(hcd, udev, state);

	mel = calculate_max_exit_latency(udev, state, hub_encoded_timeout);

	if (mel < 0) {