xhci: Return if xHCI doesn't support LPM

commit f0c472a6da51f9fac15e80fe2fd9c83b68754cff upstream.

Just return if xHCI is quirked to disable LPM. We can save some time
from reading registers and doing spinlocks.

Add stable tag as we want this patch together with the next one,
"Poll for U0 after disabling USB2 LPM" which fixes a suspend issue
for some USB2 LPM devices

Cc: [email protected]
Signed-off-by: Kai-Heng Feng <[email protected]>
Signed-off-by: Mathias Nyman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Kai-Heng Feng 2020-06-24 16:59:48 +03:00 • committed by Sasha Levin
commit d6522bc320

View file

@ -4391,6 +4391,9 @@ static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
int hird, exit_latency;
int ret;
if (xhci->quirks & XHCI_HW_LPM_DISABLE)
return -EPERM;
if (hcd->speed >= HCD_USB3 || !xhci->hw_lpm_support ||
!udev->lpm_capable)
return -EPERM;
@ -4413,7 +4416,7 @@ 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 && !(xhci->quirks & XHCI_HW_LPM_DISABLE)) {
if (enable) {
/* 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