ACPI: handle re-enumeration, when acpi_devices might already exist (e3b87f8a) · Commits · 戴 / test

acpi_bus_scan() traverses the namespace to enumerate devices and uses acpi_add_single_object() to create acpi_devices. When the platform notifies us of a hot-plug event, we need to traverse part of the namespace again to figure out what appeared or disappeared. (We don't yet call acpi_bus_scan() during hot-plug, but I plan to do that in the future.) This patch makes acpi_add_single_object() notice when we already have an acpi_device, so we don't need to make a new one. Signed-off-by:

Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by:

Len Brown <len.brown@intel.com>

drivers/acpi/scan.c

+11 −8

Original line number	Diff line number	Diff line
		@@ -1400,10 +1400,10 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
		void context, void *return_value)
		{
		struct acpi_bus_ops *ops = context;
		struct acpi_device *device = NULL;
		acpi_status status;
		int type;
		unsigned long long sta;
		struct acpi_device *device;
		acpi_status status;
		int result;

		result = acpi_bus_type_and_status(handle, &type, &sta);
		@@ -1414,13 +1414,16 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
		!(sta & ACPI_STA_DEVICE_FUNCTIONING))
		return AE_CTRL_DEPTH;

		if (ops->acpi_op_add)
		status = acpi_add_single_object(&device, handle, type, sta,
		ops);
		else
		status = acpi_bus_get_device(handle, &device);
		/*
		* We may already have an acpi_device from a previous enumeration. If
		* so, we needn't add it again, but we may still have to start it.
		*/
		device = NULL;
		acpi_bus_get_device(handle, &device);
		if (ops->acpi_op_add && !device)
		acpi_add_single_object(&device, handle, type, sta, ops);

		if (ACPI_FAILURE(status))
		if (!device)
		return AE_CTRL_DEPTH;

		if (ops->acpi_op_start && !(ops->acpi_op_add)) {

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