diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst
index a99ee402b212..b053b0c3d696 100644
--- a/Documentation/firmware-guide/acpi/index.rst
+++ b/Documentation/firmware-guide/acpi/index.rst
@@ -26,5 +26,6 @@ ACPI Support
    acpi-lid
    lpit
    video_extension
+   non-d0-probe
    extcon-intel-int3496
    intel-pmc-mux
diff --git a/Documentation/firmware-guide/acpi/non-d0-probe.rst b/Documentation/firmware-guide/acpi/non-d0-probe.rst
new file mode 100644
index 000000000000..7afd16701a02
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/non-d0-probe.rst
@@ -0,0 +1,78 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========================================
+Probing devices in other D states than 0
+========================================
+
+Introduction
+============
+
+In some cases it may be preferred to leave certain devices powered off for the
+entire system bootup if powering on these devices has adverse side effects,
+beyond just powering on the said device.
+
+How it works
+============
+
+The _DSC (Device State for Configuration) object that evaluates to an integer
+may be used to tell Linux the highest allowed D state for a device during
+probe. The support for _DSC requires support from the kernel bus type if the
+bus driver normally sets the device in D0 state for probe.
+
+The downside of using _DSC is that as the device is not powered on, even if
+there's a problem with the device, the driver likely probes just fine but the
+first user will find out the device doesn't work, instead of a failure at probe
+time. This feature should thus be used sparingly.
+
+I²C
+---
+
+If an I²C driver indicates its support for this by setting the
+I2C_DRV_ACPI_WAIVE_D0_PROBE flag in struct i2c_driver.flags field and the
+_DSC object evaluates to integer higher than the D state of the device,
+the device will not be powered on (put in D0 state) for probe.
+
+D states
+--------
+
+The D states and thus also the allowed values for _DSC are listed below. Refer
+to [1] for more information on device power states.
+
+.. code-block:: text
+
+	Number	State	Description
+	0	D0	Device fully powered on
+	1	D1
+	2	D2
+	3	D3hot
+	4	D3cold	Off
+
+References
+==========
+
+[1] https://uefi.org/specifications/ACPI/6.4/02_Definition_of_Terms/Definition_of_Terms.html#device-power-state-definitions
+
+Example
+=======
+
+An ASL example describing an ACPI device using _DSC object to tell Operating
+System the device should remain powered off during probe looks like this. Some
+objects not relevant from the example point of view have been omitted.
+
+.. code-block:: text
+
+	Device (CAM0)
+	{
+		Name (_HID, "SONY319A")
+		Name (_UID, Zero)
+		Name (_CRS, ResourceTemplate ()
+		{
+			I2cSerialBus(0x0020, ControllerInitiated, 0x00061A80,
+				     AddressingMode7Bit, "\\_SB.PCI0.I2C0",
+				     0x00, ResourceConsumer)
+		})
+		Method (_DSC, 0, NotSerialized)
+		{
+			Return (0x4)
+		}
+	}
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 0028b6b51c87..19b33c028f35 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -1400,4 +1400,30 @@ bool acpi_storage_d3(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(acpi_storage_d3);
 
+/**
+ * acpi_dev_state_d0 - Tell if the device is in D0 power state
+ * @dev: Physical device the ACPI power state of which to check
+ *
+ * On a system without ACPI, return true. On a system with ACPI, return true if
+ * the current ACPI power state of the device is D0, or false otherwise.
+ *
+ * Note that the power state of a device is not well-defined after it has been
+ * passed to acpi_device_set_power() and before that function returns, so it is
+ * not valid to ask for the ACPI power state of the device in that time frame.
+ *
+ * This function is intended to be used in a driver's probe or remove
+ * function. See Documentation/firmware-guide/acpi/low-power-probe.rst for
+ * more information.
+ */
+bool acpi_dev_state_d0(struct device *dev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (!adev)
+		return true;
+
+	return adev->power.state == ACPI_STATE_D0;
+}
+EXPORT_SYMBOL_GPL(acpi_dev_state_d0);
+
 #endif /* CONFIG_PM */
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index e629e891d1bb..a6366d3f0c78 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -133,7 +133,7 @@ static unsigned int ec_storm_threshold  __read_mostly = 8;
 module_param(ec_storm_threshold, uint, 0644);
 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 
-static bool ec_freeze_events __read_mostly = false;
+static bool ec_freeze_events __read_mostly;
 module_param(ec_freeze_events, bool, 0644);
 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 
@@ -177,7 +177,7 @@ struct acpi_ec *first_ec;
 EXPORT_SYMBOL(first_ec);
 
 static struct acpi_ec *boot_ec;
-static bool boot_ec_is_ecdt = false;
+static bool boot_ec_is_ecdt;
 static struct workqueue_struct *ec_wq;
 static struct workqueue_struct *ec_query_wq;
 
@@ -2152,6 +2152,13 @@ static const struct dmi_system_id acpi_ec_no_wakeup[] = {
 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
 		},
 	},
+	{
+		.ident = "HP ZHAN 66 Pro",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
+		},
+	},
 	{ },
 };
 
diff --git a/drivers/acpi/pmic/intel_pmic.c b/drivers/acpi/pmic/intel_pmic.c
index a371f273f99d..9cde299eba88 100644
--- a/drivers/acpi/pmic/intel_pmic.c
+++ b/drivers/acpi/pmic/intel_pmic.c
@@ -211,31 +211,36 @@ static acpi_status intel_pmic_regs_handler(u32 function,
 		void *handler_context, void *region_context)
 {
 	struct intel_pmic_opregion *opregion = region_context;
-	int result = 0;
+	int result = -EINVAL;
 
-	switch (address) {
-	case 0:
-		return AE_OK;
-	case 1:
-		opregion->ctx.addr |= (*value64 & 0xff) << 8;
-		return AE_OK;
-	case 2:
-		opregion->ctx.addr |= *value64 & 0xff;
-		return AE_OK;
-	case 3:
-		opregion->ctx.val = *value64 & 0xff;
-		return AE_OK;
-	case 4:
-		if (*value64) {
-			result = regmap_write(opregion->regmap, opregion->ctx.addr,
-					      opregion->ctx.val);
-		} else {
-			result = regmap_read(opregion->regmap, opregion->ctx.addr,
-					     &opregion->ctx.val);
-			if (result == 0)
-				*value64 = opregion->ctx.val;
+	if (function == ACPI_WRITE) {
+		switch (address) {
+		case 0:
+			return AE_OK;
+		case 1:
+			opregion->ctx.addr |= (*value64 & 0xff) << 8;
+			return AE_OK;
+		case 2:
+			opregion->ctx.addr |= *value64 & 0xff;
+			return AE_OK;
+		case 3:
+			opregion->ctx.val = *value64 & 0xff;
+			return AE_OK;
+		case 4:
+			if (*value64) {
+				result = regmap_write(opregion->regmap, opregion->ctx.addr,
+						      opregion->ctx.val);
+			} else {
+				result = regmap_read(opregion->regmap, opregion->ctx.addr,
+						     &opregion->ctx.val);
+			}
+			opregion->ctx.addr = 0;
 		}
-		memset(&opregion->ctx, 0x00, sizeof(opregion->ctx));
+	}
+
+	if (function == ACPI_READ && address == 3) {
+		*value64 = opregion->ctx.val;
+		return AE_OK;
 	}
 
 	if (result < 0) {
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 112256154880..5dcb02ededbc 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -757,13 +757,11 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 
 	mutex_lock(&acpi_device_lock);
 
-	if (dev->wakeup.prepare_count > 1) {
-		dev->wakeup.prepare_count--;
-		goto out;
-	}
-
 	/* Do nothing if wakeup power has not been enabled for this device. */
-	if (!dev->wakeup.prepare_count)
+	if (dev->wakeup.prepare_count <= 0)
+		goto out;
+
+	if (--dev->wakeup.prepare_count > 0)
 		goto out;
 
 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index dce2c291b982..a50f1967c73d 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1017,6 +1017,7 @@ static void acpi_bus_init_power_state(struct acpi_device *device, int state)
 
 static void acpi_bus_get_power_flags(struct acpi_device *device)
 {
+	unsigned long long dsc = ACPI_STATE_D0;
 	u32 i;
 
 	/* Presence of _PS0|_PR0 indicates 'power manageable' */
@@ -1038,6 +1039,9 @@ static void acpi_bus_get_power_flags(struct acpi_device *device)
 	if (acpi_has_method(device->handle, "_DSW"))
 		device->power.flags.dsw_present = 1;
 
+	acpi_evaluate_integer(device->handle, "_DSC", NULL, &dsc);
+	device->power.state_for_enumeration = dsc;
+
 	/*
 	 * Enumerate supported power management states
 	 */
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 33474fd96991..068e393ea0c6 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -115,7 +115,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	 */
 	{
 	 .callback = video_detect_force_vendor,
-	 .ident = "X360",
+	 /* X360 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
@@ -124,7 +124,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_vendor,
-	.ident = "Asus UL30VT",
+	/* Asus UL30VT */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
@@ -132,7 +132,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_vendor,
-	.ident = "Asus UL30A",
+	/* Asus UL30A */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
@@ -140,7 +140,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_vendor,
-	.ident = "GIGABYTE GB-BXBT-2807",
+	/* GIGABYTE GB-BXBT-2807 */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "GB-BXBT-2807"),
@@ -148,12 +148,20 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_vendor,
-	.ident = "Sony VPCEH3U1E",
+	/* Sony VPCEH3U1E */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "VPCEH3U1E"),
 		},
 	},
+	{
+	.callback = video_detect_force_vendor,
+	/* Xiaomi Mi Pad 2 */
+	.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Xiaomi Inc"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Mipad2"),
+		},
+	},
 
 	/*
 	 * These models have a working acpi_video backlight control, and using
@@ -164,7 +172,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	 */
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "ThinkPad T420",
+	 /* ThinkPad T420 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
@@ -172,7 +180,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "ThinkPad T520",
+	 /* ThinkPad T520 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
@@ -180,7 +188,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "ThinkPad X201s",
+	 /* ThinkPad X201s */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
@@ -188,7 +196,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "ThinkPad X201T",
+	 /* ThinkPad X201T */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201T"),
@@ -199,7 +207,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
 	 .callback = video_detect_force_video,
-	 .ident = "HP ENVY 15 Notebook",
+	 /* HP ENVY 15 Notebook */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
@@ -207,7 +215,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 870Z5E/880Z5E/680Z5E",
+	 /* SAMSUNG 870Z5E/880Z5E/680Z5E */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"),
@@ -215,7 +223,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V",
+	 /* SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
@@ -225,7 +233,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 3570R/370R/470R/450R/510R/4450RV",
+	 /* SAMSUNG 3570R/370R/470R/450R/510R/4450RV */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
@@ -235,7 +243,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1557060 */
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 670Z5E",
+	 /* SAMSUNG 670Z5E */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "670Z5E"),
@@ -244,7 +252,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 730U3E/740U3E",
+	 /* SAMSUNG 730U3E/740U3E */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"),
@@ -253,7 +261,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D",
+	 /* SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
@@ -263,7 +271,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */
 	 .callback = video_detect_force_video,
-	 .ident = "Dell XPS14 L421X",
+	 /* Dell XPS14 L421X */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
@@ -272,7 +280,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
 	 .callback = video_detect_force_video,
-	 .ident = "Dell XPS15 L521X",
+	 /* Dell XPS15 L521X */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
@@ -281,7 +289,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=108971 */
 	 .callback = video_detect_force_video,
-	 .ident = "SAMSUNG 530U4E/540U4E",
+	 /* SAMSUNG 530U4E/540U4E */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "530U4E/540U4E"),
@@ -290,7 +298,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	/* https://bugs.launchpad.net/bugs/1894667 */
 	{
 	 .callback = video_detect_force_video,
-	 .ident = "HP 635 Notebook",
+	 /* HP 635 Notebook */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP 635 Notebook PC"),
@@ -301,7 +309,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1201530 */
 	 .callback = video_detect_force_native,
-	 .ident = "Lenovo Ideapad S405",
+	 /* Lenovo Ideapad S405 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"),
@@ -310,7 +318,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
 	 .callback = video_detect_force_native,
-	 .ident = "Lenovo Ideapad Z570",
+	 /* Lenovo Ideapad Z570 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "102434U"),
@@ -318,7 +326,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_native,
-	 .ident = "Lenovo E41-25",
+	 /* Lenovo E41-25 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "81FS"),
@@ -326,7 +334,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_native,
-	 .ident = "Lenovo E41-45",
+	 /* Lenovo E41-45 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "82BK"),
@@ -335,7 +343,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */
 	 .callback = video_detect_force_native,
-	 .ident = "Apple MacBook Pro 12,1",
+	 /* Apple MacBook Pro 12,1 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro12,1"),
@@ -343,7 +351,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_native,
-	 .ident = "Dell Vostro V131",
+	 /* Dell Vostro V131 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
@@ -352,7 +360,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1123661 */
 	 .callback = video_detect_force_native,
-	 .ident = "Dell XPS 17 L702X",
+	 /* Dell XPS 17 L702X */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L702X"),
@@ -360,7 +368,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_native,
-	 .ident = "Dell Precision 7510",
+	 /* Dell Precision 7510 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
@@ -368,7 +376,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_native,
-	 .ident = "Acer Aspire 5738z",
+	 /* Acer Aspire 5738z */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5738"),
@@ -378,7 +386,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	{
 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=207835 */
 	 .callback = video_detect_force_native,
-	 .ident = "Acer TravelMate 5735Z",
+	 /* Acer TravelMate 5735Z */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate 5735Z"),
@@ -387,7 +395,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_native,
-	.ident = "ASUSTeK COMPUTER INC. GA401",
+	/* ASUSTeK COMPUTER INC. GA401 */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "GA401"),
@@ -395,7 +403,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_native,
-	.ident = "ASUSTeK COMPUTER INC. GA502",
+	/* ASUSTeK COMPUTER INC. GA502 */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "GA502"),
@@ -403,7 +411,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	.callback = video_detect_force_native,
-	.ident = "ASUSTeK COMPUTER INC. GA503",
+	/* ASUSTeK COMPUTER INC. GA503 */
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "GA503"),
@@ -416,7 +424,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	 */
 	{
 	 .callback = video_detect_force_none,
-	 .ident = "Dell OptiPlex 9020M",
+	 /* Dell OptiPlex 9020M */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 9020M"),
@@ -424,7 +432,7 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 	},
 	{
 	 .callback = video_detect_force_none,
-	 .ident = "MSI MS-7721",
+	 /* MSI MS-7721 */
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "MS-7721"),
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 80631f93ad2f..92c1cc07ed46 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -522,6 +522,16 @@ struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 }
 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 
+bool i2c_acpi_waive_d0_probe(struct device *dev)
+{
+	struct i2c_driver *driver = to_i2c_driver(dev->driver);
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
+		adev && adev->power.state_for_enumeration >= adev->power.state;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
+
 #ifdef CONFIG_ACPI_I2C_OPREGION
 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 		u8 cmd, u8 *data, u8 data_len)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 54964fbe3f03..f193f9058584 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -551,7 +551,8 @@ static int i2c_device_probe(struct device *dev)
 	if (status < 0)
 		goto err_clear_wakeup_irq;
 
-	status = dev_pm_domain_attach(&client->dev, true);
+	status = dev_pm_domain_attach(&client->dev,
+				      !i2c_acpi_waive_d0_probe(dev));
 	if (status)
 		goto err_clear_wakeup_irq;
 
@@ -590,7 +591,7 @@ static int i2c_device_probe(struct device *dev)
 err_release_driver_resources:
 	devres_release_group(&client->dev, client->devres_group_id);
 err_detach_pm_domain:
-	dev_pm_domain_detach(&client->dev, true);
+	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
 err_clear_wakeup_irq:
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -621,7 +622,7 @@ static void i2c_device_remove(struct device *dev)
 
 	devres_release_group(&client->dev, client->devres_group_id);
 
-	dev_pm_domain_detach(&client->dev, true);
+	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
 	if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator)
 		regulator_disable(adap->bus_regulator);
 
diff --git a/drivers/media/i2c/imx319.c b/drivers/media/i2c/imx319.c
index dba0854ab5aa..daa976858e29 100644
--- a/drivers/media/i2c/imx319.c
+++ b/drivers/media/i2c/imx319.c
@@ -140,6 +140,8 @@ struct imx319 {
 
 	/* Streaming on/off */
 	bool streaming;
+	/* True if the device has been identified */
+	bool identified;
 };
 
 static const struct imx319_reg imx319_global_regs[] = {
@@ -2084,6 +2086,31 @@ imx319_set_pad_format(struct v4l2_subdev *sd,
 	return 0;
 }
 
+/* Verify chip ID */
+static int imx319_identify_module(struct imx319 *imx319)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&imx319->sd);
+	int ret;
+	u32 val;
+
+	if (imx319->identified)
+		return 0;
+
+	ret = imx319_read_reg(imx319, IMX319_REG_CHIP_ID, 2, &val);
+	if (ret)
+		return ret;
+
+	if (val != IMX319_CHIP_ID) {
+		dev_err(&client->dev, "chip id mismatch: %x!=%x",
+			IMX319_CHIP_ID, val);
+		return -EIO;
+	}
+
+	imx319->identified = true;
+
+	return 0;
+}
+
 /* Start streaming */
 static int imx319_start_streaming(struct imx319 *imx319)
 {
@@ -2091,6 +2118,10 @@ static int imx319_start_streaming(struct imx319 *imx319)
 	const struct imx319_reg_list *reg_list;
 	int ret;
 
+	ret = imx319_identify_module(imx319);
+	if (ret)
+		return ret;
+
 	/* Global Setting */
 	reg_list = &imx319_global_setting;
 	ret = imx319_write_regs(imx319, reg_list->regs, reg_list->num_of_regs);
@@ -2206,26 +2237,6 @@ error:
 	return ret;
 }
 
-/* Verify chip ID */
-static int imx319_identify_module(struct imx319 *imx319)
-{
-	struct i2c_client *client = v4l2_get_subdevdata(&imx319->sd);
-	int ret;
-	u32 val;
-
-	ret = imx319_read_reg(imx319, IMX319_REG_CHIP_ID, 2, &val);
-	if (ret)
-		return ret;
-
-	if (val != IMX319_CHIP_ID) {
-		dev_err(&client->dev, "chip id mismatch: %x!=%x",
-			IMX319_CHIP_ID, val);
-		return -EIO;
-	}
-
-	return 0;
-}
-
 static const struct v4l2_subdev_core_ops imx319_subdev_core_ops = {
 	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
 	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
@@ -2420,6 +2431,7 @@ out_err:
 static int imx319_probe(struct i2c_client *client)
 {
 	struct imx319 *imx319;
+	bool full_power;
 	int ret;
 	u32 i;
 
@@ -2432,11 +2444,14 @@ static int imx319_probe(struct i2c_client *client)
 	/* Initialize subdev */
 	v4l2_i2c_subdev_init(&imx319->sd, client, &imx319_subdev_ops);
 
-	/* Check module identity */
-	ret = imx319_identify_module(imx319);
-	if (ret) {
-		dev_err(&client->dev, "failed to find sensor: %d", ret);
-		goto error_probe;
+	full_power = acpi_dev_state_d0(&client->dev);
+	if (full_power) {
+		/* Check module identity */
+		ret = imx319_identify_module(imx319);
+		if (ret) {
+			dev_err(&client->dev, "failed to find sensor: %d", ret);
+			goto error_probe;
+		}
 	}
 
 	imx319->hwcfg = imx319_get_hwcfg(&client->dev);
@@ -2488,11 +2503,9 @@ static int imx319_probe(struct i2c_client *client)
 	if (ret < 0)
 		goto error_media_entity;
 
-	/*
-	 * Device is already turned on by i2c-core with ACPI domain PM.
-	 * Enable runtime PM and turn off the device.
-	 */
-	pm_runtime_set_active(&client->dev);
+	/* Set the device's state to active if it's in D0 state. */
+	if (full_power)
+		pm_runtime_set_active(&client->dev);
 	pm_runtime_enable(&client->dev);
 	pm_runtime_idle(&client->dev);
 
@@ -2545,6 +2558,7 @@ static struct i2c_driver imx319_i2c_driver = {
 	},
 	.probe_new = imx319_probe,
 	.remove = imx319_remove,
+	.flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 module_i2c_driver(imx319_i2c_driver);
 
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 305ffad131a2..49ab656e8a96 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -595,6 +595,7 @@ static int at24_probe(struct i2c_client *client)
 	bool i2c_fn_i2c, i2c_fn_block;
 	unsigned int i, num_addresses;
 	struct at24_data *at24;
+	bool full_power;
 	struct regmap *regmap;
 	bool writable;
 	u8 test_byte;
@@ -747,14 +748,16 @@ static int at24_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, at24);
 
-	err = regulator_enable(at24->vcc_reg);
-	if (err) {
-		dev_err(dev, "Failed to enable vcc regulator\n");
-		return err;
-	}
+	full_power = acpi_dev_state_d0(&client->dev);
+	if (full_power) {
+		err = regulator_enable(at24->vcc_reg);
+		if (err) {
+			dev_err(dev, "Failed to enable vcc regulator\n");
+			return err;
+		}
 
-	/* enable runtime pm */
-	pm_runtime_set_active(dev);
+		pm_runtime_set_active(dev);
+	}
 	pm_runtime_enable(dev);
 
 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
@@ -766,15 +769,18 @@ static int at24_probe(struct i2c_client *client)
 	}
 
 	/*
-	 * Perform a one-byte test read to verify that the
-	 * chip is functional.
+	 * Perform a one-byte test read to verify that the chip is functional,
+	 * unless powering on the device is to be avoided during probe (i.e.
+	 * it's powered off right now).
 	 */
-	err = at24_read(at24, 0, &test_byte, 1);
-	if (err) {
-		pm_runtime_disable(dev);
-		if (!pm_runtime_status_suspended(dev))
-			regulator_disable(at24->vcc_reg);
-		return -ENODEV;
+	if (full_power) {
+		err = at24_read(at24, 0, &test_byte, 1);
+		if (err) {
+			pm_runtime_disable(dev);
+			if (!pm_runtime_status_suspended(dev))
+				regulator_disable(at24->vcc_reg);
+			return -ENODEV;
+		}
 	}
 
 	pm_runtime_idle(dev);
@@ -794,9 +800,11 @@ static int at24_remove(struct i2c_client *client)
 	struct at24_data *at24 = i2c_get_clientdata(client);
 
 	pm_runtime_disable(&client->dev);
-	if (!pm_runtime_status_suspended(&client->dev))
-		regulator_disable(at24->vcc_reg);
-	pm_runtime_set_suspended(&client->dev);
+	if (acpi_dev_state_d0(&client->dev)) {
+		if (!pm_runtime_status_suspended(&client->dev))
+			regulator_disable(at24->vcc_reg);
+		pm_runtime_set_suspended(&client->dev);
+	}
 
 	return 0;
 }
@@ -833,6 +841,7 @@ static struct i2c_driver at24_driver = {
 	.probe_new = at24_probe,
 	.remove = at24_remove,
 	.id_table = at24_ids,
+	.flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 
 static int __init at24_init(void)
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 53b6e9f9de7b..480f9207a4c6 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -278,6 +278,7 @@ struct acpi_device_power {
 	int state;		/* Current state */
 	struct acpi_device_power_flags flags;
 	struct acpi_device_power_state states[ACPI_D_STATE_COUNT];	/* Power states (D0-D3Cold) */
+	u8 state_for_enumeration; /* Deepest power state for enumeration */
 };
 
 struct acpi_dep_data {
diff --git a/include/acpi/platform/acgcc.h b/include/acpi/platform/acgcc.h
index 20ecb004f5a4..33ad282bd338 100644
--- a/include/acpi/platform/acgcc.h
+++ b/include/acpi/platform/acgcc.h
@@ -10,25 +10,12 @@
 #ifndef __ACGCC_H__
 #define __ACGCC_H__
 
-/*
- * Use compiler specific <stdarg.h> is a good practice for even when
- * -nostdinc is specified (i.e., ACPI_USE_STANDARD_HEADERS undefined.
- */
 #ifndef va_arg
-#ifdef ACPI_USE_BUILTIN_STDARG
-typedef __builtin_va_list va_list;
-#define va_start(v, l)          __builtin_va_start(v, l)
-#define va_end(v)               __builtin_va_end(v)
-#define va_arg(v, l)            __builtin_va_arg(v, l)
-#define va_copy(d, s)           __builtin_va_copy(d, s)
-#else
 #ifdef __KERNEL__
 #include <linux/stdarg.h>
 #else
-/* Used to build acpi tools */
 #include <stdarg.h>
 #endif /* __KERNEL__ */
-#endif /* ACPI_USE_BUILTIN_STDARG */
 #endif /* ! va_arg */
 
 #define ACPI_INLINE             __inline__
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 375715b0535f..143ce7e0bee1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1014,6 +1014,7 @@ int acpi_subsys_runtime_suspend(struct device *dev);
 int acpi_subsys_runtime_resume(struct device *dev);
 int acpi_dev_pm_attach(struct device *dev, bool power_on);
 bool acpi_storage_d3(struct device *dev);
+bool acpi_dev_state_d0(struct device *dev);
 #else
 static inline int acpi_subsys_runtime_suspend(struct device *dev) { return 0; }
 static inline int acpi_subsys_runtime_resume(struct device *dev) { return 0; }
@@ -1025,6 +1026,10 @@ static inline bool acpi_storage_d3(struct device *dev)
 {
 	return false;
 }
+static inline bool acpi_dev_state_d0(struct device *dev)
+{
+	return true;
+}
 #endif
 
 #if defined(CONFIG_ACPI) && defined(CONFIG_PM_SLEEP)
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 2ce3efbe9198..16119ac1aa97 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -11,6 +11,7 @@
 #define _LINUX_I2C_H
 
 #include <linux/acpi.h>		/* for acpi_handle */
+#include <linux/bits.h>
 #include <linux/mod_devicetable.h>
 #include <linux/device.h>	/* for struct device */
 #include <linux/sched.h>	/* for completion */
@@ -222,6 +223,15 @@ enum i2c_alert_protocol {
 	I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
 };
 
+/**
+ * enum i2c_driver_flags - Flags for an I2C device driver
+ *
+ * @I2C_DRV_ACPI_WAIVE_D0_PROBE: Don't put the device in D0 state for probe
+ */
+enum i2c_driver_flags {
+	I2C_DRV_ACPI_WAIVE_D0_PROBE = BIT(0),
+};
+
 /**
  * struct i2c_driver - represent an I2C device driver
  * @class: What kind of i2c device we instantiate (for detect)
@@ -236,6 +246,7 @@ enum i2c_alert_protocol {
  * @detect: Callback for device detection
  * @address_list: The I2C addresses to probe (for detect)
  * @clients: List of detected clients we created (for i2c-core use only)
+ * @flags: A bitmask of flags defined in &enum i2c_driver_flags
  *
  * The driver.owner field should be set to the module owner of this driver.
  * The driver.name field should be set to the name of this driver.
@@ -294,6 +305,8 @@ struct i2c_driver {
 	int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
 	const unsigned short *address_list;
 	struct list_head clients;
+
+	u32 flags;
 };
 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 
@@ -1015,6 +1028,7 @@ u32 i2c_acpi_find_bus_speed(struct device *dev);
 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 				       struct i2c_board_info *info);
 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
+bool i2c_acpi_waive_d0_probe(struct device *dev);
 #else
 static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
 					     struct acpi_resource_i2c_serialbus **i2c)
@@ -1038,6 +1052,10 @@ static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle ha
 {
 	return NULL;
 }
+static inline bool i2c_acpi_waive_d0_probe(struct device *dev)
+{
+	return false;
+}
 #endif /* CONFIG_ACPI */
 
 #endif /* _LINUX_I2C_H */