[PATCH v1] ACPI: glue: Reduce debug noise from acpi_device_notify()

[PATCH v1] ACPI: glue: Reduce debug noise from acpi_device_notify()

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

When debug is enabled in the ACPI glue code that handles binding
devices to ACPI companions, acpi_device_notify() produces a lot of
message noise related to devices that have no ACPI companions.

Reduce that noise by checking the most obvious cases, ACPI device
objects and devices without a bus type, directly and returning from
acpi_device_notify() in these cases without printing any debug
messages.

Also make the debug messages that get printed more informative and
change the format prefix to "ACPI/glue", so it is easier to filter
these messages.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/glue.c |   34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -6,7 +6,7 @@
  * Copyright (c) 2005 Intel Corp.
  */
 
-#define pr_fmt(fmt) "ACPI: " fmt
+#define pr_fmt(fmt) "ACPI/glue: " fmt
 
 #include <linux/acpi_iort.h>
 #include <linux/export.h>
@@ -354,22 +354,33 @@ void acpi_device_notify(struct device *d
 	struct acpi_device *adev;
 	int ret;
 
+	/* ACPI devices have no ACPI companions. */
+	if (dev->bus == &acpi_bus_type)
+		return;
+
 	ret = acpi_bind_one(dev, NULL);
 	if (ret) {
-		struct acpi_bus_type *type = acpi_get_bus_type(dev);
-
-		if (!type)
-			goto err;
+		struct acpi_bus_type *type;
 
+		/* Skip devices without bus types. */
+		if (!dev->bus)
+			return;
+
+		type = acpi_get_bus_type(dev);
+		if (!type) {
+			dev_dbg(dev, "No matching ACPI bus type description\n");
+			return;
+		}
 		adev = type->find_companion(dev);
 		if (!adev) {
 			dev_dbg(dev, "ACPI companion not found\n");
-			goto err;
+			return;
 		}
 		ret = acpi_bind_one(dev, adev);
-		if (ret)
-			goto err;
-
+		if (ret) {
+			dev_dbg(dev, "Binding to ACPI companion failed\n");
+			return;
+		}
 		if (type->setup) {
 			type->setup(dev);
 			goto done;
@@ -391,11 +402,6 @@ void acpi_device_notify(struct device *d
 done:
 	acpi_handle_debug(ACPI_HANDLE(dev), "Bound to device %s\n",
 			  dev_name(dev));
-
-	return;
-
-err:
-	dev_dbg(dev, "No ACPI support\n");
 }
 
 void acpi_device_notify_remove(struct device *dev)

Re: [PATCH v1] ACPI: glue: Reduce debug noise from acpi_device_notify()

[Andy Shevchenko]

On Fri, Sep 04, 2026 at 02:55:03PM +0200, Rafael J. Wysocki wrote:
> From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> 
> When debug is enabled in the ACPI glue code that handles binding
> devices to ACPI companions, acpi_device_notify() produces a lot of
> message noise related to devices that have no ACPI companions.
> 
> Reduce that noise by checking the most obvious cases, ACPI device
> objects and devices without a bus type, directly and returning from
> acpi_device_notify() in these cases without printing any debug
> messages.
> 
> Also make the debug messages that get printed more informative and
> change the format prefix to "ACPI/glue", so it is easier to filter
> these messages.

I would argue that the consistent formatting will be "ACPI: glue: "

$ git grep -n 'pr_fmt.*ACPI: [^"]'  -- drivers/acpi/ | wc -l
24

The / is used only in two cases: acpi/hmat and acpi/mrrm.

-- 
With Best Regards,
Andy Shevchenko