From cd702d18c882d5a4ea44bbdb38edd5d5577ef640 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Mon, 16 Jan 2023 16:22:15 +0200 Subject: usb: acpi: add helper to check port lpm capability using acpi _DSM Add a helper to evaluate ACPI usb device specific method (_DSM) provided in case the USB3 port shouldn't enter U1 and U2 link states. This _DSM was added as port specific retimer configuration may lead to exit latencies growing beyond U1/U2 exit limits, and OS needs a way to find which ports can't support U1/U2 link power management states. This _DSM is also used by windows: Link: https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/usb-device-specific-method---dsm- Some patch issues found in testing resolved by Ron Lee Cc: stable@vger.kernel.org Tested-by: Ron Lee Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20230116142216.1141605-7-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/usb.h b/include/linux/usb.h index 7d5325d47c45..04a7e94fb772 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -774,11 +774,14 @@ extern struct device *usb_intf_get_dma_device(struct usb_interface *intf); extern int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable); extern bool usb_acpi_power_manageable(struct usb_device *hdev, int index); +extern int usb_acpi_port_lpm_incapable(struct usb_device *hdev, int index); #else static inline int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable) { return 0; } static inline bool usb_acpi_power_manageable(struct usb_device *hdev, int index) { return true; } +static inline int usb_acpi_port_lpm_incapable(struct usb_device *hdev, int index) + { return 0; } #endif /* USB autosuspend and autoresume */ -- cgit v1.2.3