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authorMathias Nyman <mathias.nyman@linux.intel.com>2023-01-16 17:22:15 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-01-17 18:37:24 +0300
commitcd702d18c882d5a4ea44bbdb38edd5d5577ef640 (patch)
tree1f85d916c9e56d6751b58fa60f67f4185f705a5e /drivers/usb/core
parent0522b9a1653048440da5f21747f21e498b9220d1 (diff)
downloadlinux-cd702d18c882d5a4ea44bbdb38edd5d5577ef640.tar.xz
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 'drivers/usb/core')
-rw-r--r--drivers/usb/core/usb-acpi.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
index 6d93428432f1..533baa85083c 100644
--- a/drivers/usb/core/usb-acpi.c
+++ b/drivers/usb/core/usb-acpi.c
@@ -37,6 +37,71 @@ bool usb_acpi_power_manageable(struct usb_device *hdev, int index)
}
EXPORT_SYMBOL_GPL(usb_acpi_power_manageable);
+#define UUID_USB_CONTROLLER_DSM "ce2ee385-00e6-48cb-9f05-2edb927c4899"
+#define USB_DSM_DISABLE_U1_U2_FOR_PORT 5
+
+/**
+ * usb_acpi_port_lpm_incapable - check if lpm should be disabled for a port.
+ * @hdev: USB device belonging to the usb hub
+ * @index: zero based port index
+ *
+ * Some USB3 ports may not support USB3 link power management U1/U2 states
+ * due to different retimer setup. ACPI provides _DSM method which returns 0x01
+ * if U1 and U2 states should be disabled. Evaluate _DSM with:
+ * Arg0: UUID = ce2ee385-00e6-48cb-9f05-2edb927c4899
+ * Arg1: Revision ID = 0
+ * Arg2: Function Index = 5
+ * Arg3: (empty)
+ *
+ * Return 1 if USB3 port is LPM incapable, negative on error, otherwise 0
+ */
+
+int usb_acpi_port_lpm_incapable(struct usb_device *hdev, int index)
+{
+ union acpi_object *obj;
+ acpi_handle port_handle;
+ int port1 = index + 1;
+ guid_t guid;
+ int ret;
+
+ ret = guid_parse(UUID_USB_CONTROLLER_DSM, &guid);
+ if (ret)
+ return ret;
+
+ port_handle = usb_get_hub_port_acpi_handle(hdev, port1);
+ if (!port_handle) {
+ dev_dbg(&hdev->dev, "port-%d no acpi handle\n", port1);
+ return -ENODEV;
+ }
+
+ if (!acpi_check_dsm(port_handle, &guid, 0,
+ BIT(USB_DSM_DISABLE_U1_U2_FOR_PORT))) {
+ dev_dbg(&hdev->dev, "port-%d no _DSM function %d\n",
+ port1, USB_DSM_DISABLE_U1_U2_FOR_PORT);
+ return -ENODEV;
+ }
+
+ obj = acpi_evaluate_dsm(port_handle, &guid, 0,
+ USB_DSM_DISABLE_U1_U2_FOR_PORT, NULL);
+
+ if (!obj)
+ return -ENODEV;
+
+ if (obj->type != ACPI_TYPE_INTEGER) {
+ dev_dbg(&hdev->dev, "evaluate port-%d _DSM failed\n", port1);
+ ACPI_FREE(obj);
+ return -EINVAL;
+ }
+
+ if (obj->integer.value == 0x01)
+ ret = 1;
+
+ ACPI_FREE(obj);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_acpi_port_lpm_incapable);
+
/**
* usb_acpi_set_power_state - control usb port's power via acpi power
* resource