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

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Date:   Mon, 26 Aug 2019 11:05:33 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Jiri Slaby <jslaby@...e.cz>
Cc:     lenb@...nel.org, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH] ACPI / processor: don't print errors for processorIDs == 0xff

On Wednesday, August 7, 2019 1:10:37 PM CEST Jiri Slaby wrote:
> 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;
>  	}
>  
> 

Applied, thanks!