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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2023-01-16 16:22:15 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-17 16:37:24 +0100 |
| commit | cd702d18c882d5a4ea44bbdb38edd5d5577ef640 (patch) | |
| tree | 1f85d916c9e56d6751b58fa60f67f4185f705a5e /include | |
| parent | 0522b9a1653048440da5f21747f21e498b9220d1 (diff) | |
| download | linux-cd702d18c882d5a4ea44bbdb38edd5d5577ef640.tar.bz2 | |
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 <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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/usb.h | 3 |
1 files changed, 3 insertions, 0 deletions
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 */ |