linux-kernel - [PATCH] ACPI / processor: don't print errors for processorIDs == 0xff

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Message-Id: <20190807111037.27182-1-jslaby@suse.cz>
Date:   Wed,  7 Aug 2019 13:10:37 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     rjw@...ysocki.net
Cc:     lenb@...nel.org, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH] ACPI / processor: don't print errors for processorIDs == 0xff

Some platforms define their processors in this manner:
    Device (SCK0)
    {
	Name (_HID, "ACPI0004" /* Module Device */)  // _HID: Hardware ID
	Name (_UID, "CPUSCK0")  // _UID: Unique ID
	Processor (CP00, 0x00, 0x00000410, 0x06){}
	Processor (CP01, 0x02, 0x00000410, 0x06){}
	Processor (CP02, 0x04, 0x00000410, 0x06){}
	Processor (CP03, 0x06, 0x00000410, 0x06){}
	Processor (CP04, 0x01, 0x00000410, 0x06){}
	Processor (CP05, 0x03, 0x00000410, 0x06){}
	Processor (CP06, 0x05, 0x00000410, 0x06){}
	Processor (CP07, 0x07, 0x00000410, 0x06){}
	Processor (CP08, 0xFF, 0x00000410, 0x06){}
	Processor (CP09, 0xFF, 0x00000410, 0x06){}
	Processor (CP0A, 0xFF, 0x00000410, 0x06){}
	Processor (CP0B, 0xFF, 0x00000410, 0x06){}
...

The processors marked as 0xff are invalid, there are only 8 of them in
this case.

So do not print an error on ids == 0xff, just print an info message.
Actually, we could return ENODEV even on the first CPU with ID 0xff, but
ACPI spec does not forbid the 0xff value to be a processor ID. Given
0xff could be a correct one, we would break working systems if we
returned ENODEV.

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/acpi_processor.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 24f065114d42..2c4dda0787e8 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -279,9 +279,13 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	}
 
 	if (acpi_duplicate_processor_id(pr->acpi_id)) {
-		dev_err(&device->dev,
-			"Failed to get unique processor _UID (0x%x)\n",
-			pr->acpi_id);
+		if (pr->acpi_id == 0xff)
+			dev_info_once(&device->dev,
+				"Entry not well-defined, consider updating BIOS\n");
+		else
+			dev_err(&device->dev,
+				"Failed to get unique processor _UID (0x%x)\n",
+				pr->acpi_id);
 		return -ENODEV;
 	}
 
-- 
2.22.0