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-rw-r--r--Documentation/acpi/enumeration.txt57
-rw-r--r--Documentation/cpu-freq/user-guide.txt2
-rw-r--r--Documentation/devicetree/bindings/power/opp.txt448
-rw-r--r--Documentation/kernel-parameters.txt62
-rw-r--r--Documentation/power/runtime_pm.txt6
5 files changed, 535 insertions, 40 deletions
diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index 15dfce7..b731b29 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -42,7 +42,7 @@ Adding ACPI support for an existing driver should be pretty
straightforward. Here is the simplest example:
#ifdef CONFIG_ACPI
- static struct acpi_device_id mydrv_acpi_match[] = {
+ static const struct acpi_device_id mydrv_acpi_match[] = {
/* ACPI IDs here */
{ }
};
@@ -166,7 +166,7 @@ the platform device drivers. Below is an example where we add ACPI support
to at25 SPI eeprom driver (this is meant for the above ACPI snippet):
#ifdef CONFIG_ACPI
- static struct acpi_device_id at25_acpi_match[] = {
+ static const struct acpi_device_id at25_acpi_match[] = {
{ "AT25", 0 },
{ },
};
@@ -230,7 +230,7 @@ Below is an example of how to add ACPI support to the existing mpu3050
input driver:
#ifdef CONFIG_ACPI
- static struct acpi_device_id mpu3050_acpi_match[] = {
+ static const struct acpi_device_id mpu3050_acpi_match[] = {
{ "MPU3050", 0 },
{ },
};
@@ -359,3 +359,54 @@ the id should be set like:
The ACPI id "XYZ0001" is then used to lookup an ACPI device directly under
the MFD device and if found, that ACPI companion device is bound to the
resulting child platform device.
+
+Device Tree namespace link device ID
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The Device Tree protocol uses device indentification based on the "compatible"
+property whose value is a string or an array of strings recognized as device
+identifiers by drivers and the driver core. The set of all those strings may be
+regarded as a device indentification namespace analogous to the ACPI/PNP device
+ID namespace. Consequently, in principle it should not be necessary to allocate
+a new (and arguably redundant) ACPI/PNP device ID for a devices with an existing
+identification string in the Device Tree (DT) namespace, especially if that ID
+is only needed to indicate that a given device is compatible with another one,
+presumably having a matching driver in the kernel already.
+
+In ACPI, the device identification object called _CID (Compatible ID) is used to
+list the IDs of devices the given one is compatible with, but those IDs must
+belong to one of the namespaces prescribed by the ACPI specification (see
+Section 6.1.2 of ACPI 6.0 for details) and the DT namespace is not one of them.
+Moreover, the specification mandates that either a _HID or an _ADR identificaion
+object be present for all ACPI objects representing devices (Section 6.1 of ACPI
+6.0). For non-enumerable bus types that object must be _HID and its value must
+be a device ID from one of the namespaces prescribed by the specification too.
+
+The special DT namespace link device ID, PRP0001, provides a means to use the
+existing DT-compatible device identification in ACPI and to satisfy the above
+requirements following from the ACPI specification at the same time. Namely,
+if PRP0001 is returned by _HID, the ACPI subsystem will look for the
+"compatible" property in the device object's _DSD and will use the value of that
+property to identify the corresponding device in analogy with the original DT
+device identification algorithm. If the "compatible" property is not present
+or its value is not valid, the device will not be enumerated by the ACPI
+subsystem. Otherwise, it will be enumerated automatically as a platform device
+(except when an I2C or SPI link from the device to its parent is present, in
+which case the ACPI core will leave the device enumeration to the parent's
+driver) and the identification strings from the "compatible" property value will
+be used to find a driver for the device along with the device IDs listed by _CID
+(if present).
+
+Analogously, if PRP0001 is present in the list of device IDs returned by _CID,
+the identification strings listed by the "compatible" property value (if present
+and valid) will be used to look for a driver matching the device, but in that
+case their relative priority with respect to the other device IDs listed by
+_HID and _CID depends on the position of PRP0001 in the _CID return package.
+Specifically, the device IDs returned by _HID and preceding PRP0001 in the _CID
+return package will be checked first. Also in that case the bus type the device
+will be enumerated to depends on the device ID returned by _HID.
+
+It is valid to define device objects with a _HID returning PRP0001 and without
+the "compatible" property in the _DSD or a _CID as long as one of their
+ancestors provides a _DSD with a valid "compatible" property. Such device
+objects are then simply regarded as additional "blocks" providing hierarchical
+configuration information to the driver of the composite ancestor device.
diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt
index ff2f283..109e97b 100644
--- a/Documentation/cpu-freq/user-guide.txt
+++ b/Documentation/cpu-freq/user-guide.txt
@@ -196,8 +196,6 @@ affected_cpus : List of Online CPUs that require software
related_cpus : List of Online + Offline CPUs that need software
coordination of frequency.
-scaling_driver : Hardware driver for cpufreq.
-
scaling_cur_freq : Current frequency of the CPU as determined by
the governor and cpufreq core, in KHz. This is
the frequency the kernel thinks the CPU runs
diff --git a/Documentation/devicetree/bindings/power/opp.txt b/Documentation/devicetree/bindings/power/opp.txt
index 74499e5..0d5e7c9 100644
--- a/Documentation/devicetree/bindings/power/opp.txt
+++ b/Documentation/devicetree/bindings/power/opp.txt
@@ -1,8 +1,19 @@
-* Generic OPP Interface
+Generic OPP (Operating Performance Points) Bindings
+----------------------------------------------------
-SoCs have a standard set of tuples consisting of frequency and
-voltage pairs that the device will support per voltage domain. These
-are called Operating Performance Points or OPPs.
+Devices work at voltage-current-frequency combinations and some implementations
+have the liberty of choosing these. These combinations are called Operating
+Performance Points aka OPPs. This document defines bindings for these OPPs
+applicable across wide range of devices. For illustration purpose, this document
+uses CPU as a device.
+
+This document contain multiple versions of OPP binding and only one of them
+should be used per device.
+
+Binding 1: operating-points
+============================
+
+This binding only supports voltage-frequency pairs.
Properties:
- operating-points: An array of 2-tuples items, and each item consists
@@ -23,3 +34,432 @@ cpu@0 {
198000 850000
>;
};
+
+
+Binding 2: operating-points-v2
+============================
+
+* Property: operating-points-v2
+
+Devices supporting OPPs must set their "operating-points-v2" property with
+phandle to a OPP table in their DT node. The OPP core will use this phandle to
+find the operating points for the device.
+
+Devices may want to choose OPP tables at runtime and so can provide a list of
+phandles here. But only *one* of them should be chosen at runtime. This must be
+accompanied by a corresponding "operating-points-names" property, to uniquely
+identify the OPP tables.
+
+If required, this can be extended for SoC vendor specfic bindings. Such bindings
+should be documented as Documentation/devicetree/bindings/power/<vendor>-opp.txt
+and should have a compatible description like: "operating-points-v2-<vendor>".
+
+Optional properties:
+- operating-points-names: Names of OPP tables (required if multiple OPP
+ tables are present), to uniquely identify them. The same list must be present
+ for all the CPUs which are sharing clock/voltage rails and hence the OPP
+ tables.
+
+* OPP Table Node
+
+This describes the OPPs belonging to a device. This node can have following
+properties:
+
+Required properties:
+- compatible: Allow OPPs to express their compatibility. It should be:
+ "operating-points-v2".
+
+- OPP nodes: One or more OPP nodes describing voltage-current-frequency
+ combinations. Their name isn't significant but their phandle can be used to
+ reference an OPP.
+
+Optional properties:
+- opp-shared: Indicates that device nodes using this OPP Table Node's phandle
+ switch their DVFS state together, i.e. they share clock/voltage/current lines.
+ Missing property means devices have independent clock/voltage/current lines,
+ but they share OPP tables.
+
+- status: Marks the OPP table enabled/disabled.
+
+
+* OPP Node
+
+This defines voltage-current-frequency combinations along with other related
+properties.
+
+Required properties:
+- opp-hz: Frequency in Hz
+
+Optional properties:
+- opp-microvolt: voltage in micro Volts.
+
+ A single regulator's voltage is specified with an array of size one or three.
+ Single entry is for target voltage and three entries are for <target min max>
+ voltages.
+
+ Entries for multiple regulators must be present in the same order as
+ regulators are specified in device's DT node.
+
+- opp-microamp: The maximum current drawn by the device in microamperes
+ considering system specific parameters (such as transients, process, aging,
+ maximum operating temperature range etc.) as necessary. This may be used to
+ set the most efficient regulator operating mode.
+
+ Should only be set if opp-microvolt is set for the OPP.
+
+ Entries for multiple regulators must be present in the same order as
+ regulators are specified in device's DT node. If this property isn't required
+ for few regulators, then this should be marked as zero for them. If it isn't
+ required for any regulator, then this property need not be present.
+
+- clock-latency-ns: Specifies the maximum possible transition latency (in
+ nanoseconds) for switching to this OPP from any other OPP.
+
+- turbo-mode: Marks the OPP to be used only for turbo modes. Turbo mode is
+ available on some platforms, where the device can run over its operating
+ frequency for a short duration of time limited by the device's power, current
+ and thermal limits.
+
+- opp-suspend: Marks the OPP to be used during device suspend. Only one OPP in
+ the table should have this.
+
+- status: Marks the node enabled/disabled.
+
+Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together.
+
+/ {
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "arm,cortex-a9";
+ reg = <0>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 0>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cpu0_opp_table>;
+ };
+
+ cpu@1 {
+ compatible = "arm,cortex-a9";
+ reg = <1>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 0>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cpu0_opp_table>;
+ };
+ };
+
+ cpu0_opp_table: opp_table0 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000 975000 985000>;
+ opp-microamp = <70000>;
+ clock-latency-ns = <300000>;
+ opp-suspend;
+ };
+ opp01 {
+ opp-hz = <1100000000>;
+ opp-microvolt = <980000 1000000 1010000>;
+ opp-microamp = <80000>;
+ clock-latency-ns = <310000>;
+ };
+ opp02 {
+ opp-hz = <1200000000>;
+ opp-microvolt = <1025000>;
+ clock-latency-ns = <290000>;
+ turbo-mode;
+ };
+ };
+};
+
+Example 2: Single cluster, Quad-core Qualcom-krait, switches DVFS states
+independently.
+
+/ {
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "qcom,krait";
+ reg = <0>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 0>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cpu_opp_table>;
+ };
+
+ cpu@1 {
+ compatible = "qcom,krait";
+ reg = <1>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 1>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply1>;
+ operating-points-v2 = <&cpu_opp_table>;
+ };
+
+ cpu@2 {
+ compatible = "qcom,krait";
+ reg = <2>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 2>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply2>;
+ operating-points-v2 = <&cpu_opp_table>;
+ };
+
+ cpu@3 {
+ compatible = "qcom,krait";
+ reg = <3>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 3>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply3>;
+ operating-points-v2 = <&cpu_opp_table>;
+ };
+ };
+
+ cpu_opp_table: opp_table {
+ compatible = "operating-points-v2";
+
+ /*
+ * Missing opp-shared property means CPUs switch DVFS states
+ * independently.
+ */
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000 975000 985000>;
+ opp-microamp = <70000>;
+ clock-latency-ns = <300000>;
+ opp-suspend;
+ };
+ opp01 {
+ opp-hz = <1100000000>;
+ opp-microvolt = <980000 1000000 1010000>;
+ opp-microamp = <80000>;
+ clock-latency-ns = <310000>;
+ };
+ opp02 {
+ opp-hz = <1200000000>;
+ opp-microvolt = <1025000>;
+ opp-microamp = <90000;
+ lock-latency-ns = <290000>;
+ turbo-mode;
+ };
+ };
+};
+
+Example 3: Dual-cluster, Dual-core per cluster. CPUs within a cluster switch
+DVFS state together.
+
+/ {
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "arm,cortex-a7";
+ reg = <0>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 0>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cluster0_opp>;
+ };
+
+ cpu@1 {
+ compatible = "arm,cortex-a7";
+ reg = <1>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 0>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply0>;
+ operating-points-v2 = <&cluster0_opp>;
+ };
+
+ cpu@100 {
+ compatible = "arm,cortex-a15";
+ reg = <100>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 1>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply1>;
+ operating-points-v2 = <&cluster1_opp>;
+ };
+
+ cpu@101 {
+ compatible = "arm,cortex-a15";
+ reg = <101>;
+ next-level-cache = <&L2>;
+ clocks = <&clk_controller 1>;
+ clock-names = "cpu";
+ cpu-supply = <&cpu_supply1>;
+ operating-points-v2 = <&cluster1_opp>;
+ };
+ };
+
+ cluster0_opp: opp_table0 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000 975000 985000>;
+ opp-microamp = <70000>;
+ clock-latency-ns = <300000>;
+ opp-suspend;
+ };
+ opp01 {
+ opp-hz = <1100000000>;
+ opp-microvolt = <980000 1000000 1010000>;
+ opp-microamp = <80000>;
+ clock-latency-ns = <310000>;
+ };
+ opp02 {
+ opp-hz = <1200000000>;
+ opp-microvolt = <1025000>;
+ opp-microamp = <90000>;
+ clock-latency-ns = <290000>;
+ turbo-mode;
+ };
+ };
+
+ cluster1_opp: opp_table1 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp10 {
+ opp-hz = <1300000000>;
+ opp-microvolt = <1045000 1050000 1055000>;
+ opp-microamp = <95000>;
+ clock-latency-ns = <400000>;
+ opp-suspend;
+ };
+ opp11 {
+ opp-hz = <1400000000>;
+ opp-microvolt = <1075000>;
+ opp-microamp = <100000>;
+ clock-latency-ns = <400000>;
+ };
+ opp12 {
+ opp-hz = <1500000000>;
+ opp-microvolt = <1010000 1100000 1110000>;
+ opp-microamp = <95000>;
+ clock-latency-ns = <400000>;
+ turbo-mode;
+ };
+ };
+};
+
+Example 4: Handling multiple regulators
+
+/ {
+ cpus {
+ cpu@0 {
+ compatible = "arm,cortex-a7";
+ ...
+
+ cpu-supply = <&cpu_supply0>, <&cpu_supply1>, <&cpu_supply2>;
+ operating-points-v2 = <&cpu0_opp_table>;
+ };
+ };
+
+ cpu0_opp_table: opp_table0 {
+ compatible = "operating-points-v2";
+ opp-shared;
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000>, /* Supply 0 */
+ <960000>, /* Supply 1 */
+ <960000>; /* Supply 2 */
+ opp-microamp = <70000>, /* Supply 0 */
+ <70000>, /* Supply 1 */
+ <70000>; /* Supply 2 */
+ clock-latency-ns = <300000>;
+ };
+
+ /* OR */
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000 975000 985000>, /* Supply 0 */
+ <960000 965000 975000>, /* Supply 1 */
+ <960000 965000 975000>; /* Supply 2 */
+ opp-microamp = <70000>, /* Supply 0 */
+ <70000>, /* Supply 1 */
+ <70000>; /* Supply 2 */
+ clock-latency-ns = <300000>;
+ };
+
+ /* OR */
+
+ opp00 {
+ opp-hz = <1000000000>;
+ opp-microvolt = <970000 975000 985000>, /* Supply 0 */
+ <960000 965000 975000>, /* Supply 1 */
+ <960000 965000 975000>; /* Supply 2 */
+ opp-microamp = <70000>, /* Supply 0 */
+ <0>, /* Supply 1 doesn't need this */
+ <70000>; /* Supply 2 */
+ clock-latency-ns = <300000>;
+ };
+ };
+};
+
+Example 5: Multiple OPP tables
+
+/ {
+ cpus {
+ cpu@0 {
+ compatible = "arm,cortex-a7";
+ ...
+
+ cpu-supply = <&cpu_supply>
+ operating-points-v2 = <&cpu0_opp_table_slow>, <&cpu0_opp_table_fast>;
+ operating-points-names = "slow", "fast";
+ };
+ };
+
+ cpu0_opp_table_slow: opp_table_slow {
+ compatible = "operating-points-v2";
+ status = "okay";
+ opp-shared;
+
+ opp00 {
+ opp-hz = <600000000>;
+ ...
+ };
+
+ opp01 {
+ opp-hz = <800000000>;
+ ...
+ };
+ };
+
+ cpu0_opp_table_fast: opp_table_fast {
+ compatible = "operating-points-v2";
+ status = "okay";
+ opp-shared;
+
+ opp10 {
+ opp-hz = <1000000000>;
+ ...
+ };
+
+ opp11 {
+ opp-hz = <1100000000>;
+ ...
+ };
+ };
+};
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7bd4501..ae44749 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -179,11 +179,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
See also Documentation/power/runtime_pm.txt, pci=noacpi
- acpi_rsdp= [ACPI,EFI,KEXEC]
- Pass the RSDP address to the kernel, mostly used
- on machines running EFI runtime service to boot the
- second kernel for kdump.
-
acpi_apic_instance= [ACPI, IOAPIC]
Format: <int>
2: use 2nd APIC table, if available
@@ -197,6 +192,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
(e.g. thinkpad_acpi, sony_acpi, etc.) instead
of the ACPI video.ko driver.
+ acpica_no_return_repair [HW, ACPI]
+ Disable AML predefined validation mechanism
+ This mechanism can repair the evaluation result to make
+ the return objects more ACPI specification compliant.
+ This option is useful for developers to identify the
+ root cause of an AML interpreter issue when the issue
+ has something to do with the repair mechanism.
+
acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Format: <int>
@@ -225,6 +228,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
unusable. The "log_buf_len" parameter may be useful
if you need to capture more output.
+ acpi_enforce_resources= [ACPI]
+ { strict | lax | no }
+ Check for resource conflicts between native drivers
+ and ACPI OperationRegions (SystemIO and SystemMemory
+ only). IO ports and memory declared in ACPI might be
+ used by the ACPI subsystem in arbitrary AML code and
+ can interfere with legacy drivers.
+ strict (default): access to resources claimed by ACPI
+ is denied; legacy drivers trying to access reserved
+ resources will fail to bind to device using them.
+ lax: access to resources claimed by ACPI is allowed;
+ legacy drivers trying to access reserved resources
+ will bind successfully but a warning message is logged.
+ no: ACPI OperationRegions are not marked as reserved,
+ no further checks are performed.
+
acpi_force_table_verification [HW,ACPI]
Enable table checksum verification during early stage.
By default, this is disabled due to x86 early mapping
@@ -253,6 +272,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
This feature is enabled by default.
This option allows to turn off the feature.
+ acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
+ kernels.
+
acpi_no_static_ssdt [HW,ACPI]
Disable installation of static SSDTs at early boot time
By default, SSDTs contained in the RSDT/XSDT will be
@@ -263,13 +285,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
dynamic table installation which will install SSDT
tables to /sys/firmware/acpi/tables/dynamic.
- acpica_no_return_repair [HW, ACPI]
- Disable AML predefined validation mechanism
- This mechanism can repair the evaluation result to make
- the return objects more ACPI specification compliant.
- This option is useful for developers to identify the
- root cause of an AML interpreter issue when the issue
- has something to do with the repair mechanism.
+ acpi_rsdp= [ACPI,EFI,KEXEC]
+ Pass the RSDP address to the kernel, mostly used
+ on machines running EFI runtime service to boot the
+ second kernel for kdump.
acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
Format: To spoof as Windows 98: ="Microsoft Windows"
@@ -365,25 +384,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Use timer override. For some broken Nvidia NF5 boards
that require a timer override, but don't have HPET
- acpi_enforce_resources= [ACPI]
- { strict | lax | no }
- Check for resource conflicts between native drivers
- and ACPI OperationRegions (SystemIO and SystemMemory
- only). IO ports and memory declared in ACPI might be
- used by the ACPI subsystem in arbitrary AML code and
- can interfere with legacy drivers.
- strict (default): access to resources claimed by ACPI
- is denied; legacy drivers trying to access reserved
- resources will fail to bind to device using them.
- lax: access to resources claimed by ACPI is allowed;
- legacy drivers trying to access reserved resources
- will bind successfully but a warning message is logged.
- no: ACPI OperationRegions are not marked as reserved,
- no further checks are performed.
-
- acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
- kernels.
-
add_efi_memmap [EFI; X86] Include EFI memory map in
kernel's map of available physical RAM.
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 44fe1d2..e76dc0a 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -556,6 +556,12 @@ helper functions described in Section 4. In that case, pm_runtime_resume()
should be used. Of course, for this purpose the device's runtime PM has to be
enabled earlier by calling pm_runtime_enable().
+Note, if the device may execute pm_runtime calls during the probe (such as
+if it is registers with a subsystem that may call back in) then the
+pm_runtime_get_sync() call paired with a pm_runtime_put() call will be
+appropriate to ensure that the device is not put back to sleep during the
+probe. This can happen with systems such as the network device layer.
+
It may be desirable to suspend the device once ->probe() has finished.
Therefore the driver core uses the asyncronous pm_request_idle() to submit a
request to execute the subsystem-level idle callback for the device at that
generated by cgit v0.10.2 at 2024-08-26 20:16:42 (GMT)