From 424140d31ba1c613e7a087caf87723d0273f4dae Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Thu, 12 May 2022 01:04:48 +0300
Subject: [PATCH] xhci: prevent U2 link power state if Intel tier policy
prevented U1
Git-commit: 424140d31ba1c613e7a087caf87723d0273f4dae
References: jsc#PED-531
Patch-mainline: v5.19-rc1
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: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220511220450.85367-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
drivers/usb/host/xhci.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index e66a031de5a3..d957eac59ab3 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -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) {
--
2.35.3