[PATCH] PCI/ACPI: Suppress missing MCFG message

[Hanjun Guo]

Hi Jeremy,

On 2020/9/5 1:08, Jeremy Linton wrote:
> MCFG is an optional ACPI table. Given there are machines
> without PCI(e) (or it is hidden) we have been receiving
> queries/complaints about what this message means given
> its being presented as an error.
> 
> Lets only print an error if something is wrong with the
> the given table/etc. The ACPI table list printed at boot
> will continue to provide a way to detect when the table
> is missing.
> 
> Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
> ---
>   drivers/acpi/pci_mcfg.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> index 54b36b7ad47d..0bc8c012f157 100644
> --- a/drivers/acpi/pci_mcfg.c
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -279,6 +279,6 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
>   void __init pci_mmcfg_late_init(void)
>   {
>   	int err = acpi_table_parse(ACPI_SIG_MCFG, pci_mcfg_parse);

acpi_table_parse() will return errno -ENODEV and -EINVAL, and only
returns -EINVAL if the table id or the handler is NULL, which is
impossible here.

> -	if (err)
> +	if (err && err != -ENODEV)

So the error message below will never be printed, I would
prefer update the pr_err() to pr_dbg() for optional ACPI
table.

>   		pr_err("Failed to parse MCFG (%d)\n", err);
>   }

Thanks
Hanjun