usb: acpi: add helper to check port lpm capability using acpi _DSM

commit cd702d18c882d5a4ea44bbdb38edd5d5577ef640 upstream.

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 <ron.lee@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230116142216.1141605-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman
2023-01-16 16:22:15 +02:00
committed by Greg Kroah-Hartman
parent 4d70a8a9ab
commit 2551f8cbf2
2 changed files with 68 additions and 0 deletions

View File

@@ -754,11 +754,14 @@ 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 */