Re: [PATCH v3] ACPI:PRM: Reduce unnecessary printing to avoid the worries of regular users

["Rafael J. Wysocki" <rafael@xxxxxxxxxx>]

On Mon, May 12, 2025 at 3:19 AM Zhu Qiyu <qiyuzhu2@xxxxxxx> wrote:
>
> Commit 088984c8d54c ("ACPI: PRM: Find EFI_MEMORY_RUNTIME block for PRM
> handler and context") introduces non-essential printing "Failed
> to find VA for GUID: 7626C6AE-F973-429C-A91C-107D7BE298B0, PA: 0x0"
> which causes unnecessary worry for regular users.
>
> Refer to PRM Spec Section 4.1.2[1], both static data buffer address
> and ACPI parameter buffer address may be NULL if they are not needed.
> So there is no need to print out "Failed to find VA ... " to intimidate
> regular users.
>
> Link: https://uefi.org/sites/default/files/resources/Platform%20Runtime%20Mechanism%20-%20with%20legal%20notice.pdf # [1]
>
> Signed-off-by: Zhu Qiyu <qiyuzhu2@xxxxxxx>
> ---
>
> Previous versions can be found at:
> v1: https://lore.kernel.org/linux-acpi/CAJZ5v0hv0WKd-SXFhUgYs-Zpc+-PsSNOBu0r7L5TzJWgddtsKA@xxxxxxxxxxxxxx/t/#u
> v2: https://lore.kernel.org/linux-acpi/20250512010620.142155-1-qiyuzhu2@xxxxxxx/#r
>
> Changes in v2:
>  - Reduce the code changes.
> Changes in v3:
>  - Fixed title letters not showing.
>
>  drivers/acpi/prmt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index e549914a636c..28a9930267a3 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -85,7 +85,7 @@ static u64 efi_pa_va_lookup(efi_guid_t *guid, u64 pa)
>                 }
>         }
>
> -       pr_warn("Failed to find VA for GUID: %pUL, PA: 0x%llx", guid, pa);
> +       pr_info("VA for GUID: %pUL, PA: 0x%llx not found\n", guid, pa);

Thanks for following my advice, but on second thought, it would be
good to discard the message entirely if pa is zero and it is valid by
the spac, but still complain if pa is nonzero and it cannot be mapped.

So what about doing something like this in acpi_parse_prmt():

if (handler_info->static_data_buffer_address)
        th->static_data_buffer_addr = efi_pa_va_lookup(&th->guid,
handler_info->static_data_buffer_address);
else
        th->static_data_buffer_addr = 0;

and analogously for th->acpi_param_buffer_addr()?

>
>         return 0;
>  }
>
> base-commit: 92a09c47464d040866cf2b4cd052bc60555185fb
> --