On Fri, Feb 09, 2018 at 02:56:43PM -0800, Alex Hung wrote:
> In recent Intel hardware the IRQs become non-configurable after BIOS
> initializes them in PEI phase and _PRS objects are no longer included in
> ASL.
>
> This is the same as "static (non-configurable) devices do not
> specify a _PRS object" in ACPI spec. As a result, error messages
> saying "ACPI Exception: AE_NOT_FOUND, Evaluating _PRS" does not need to
> be in kernel messages all the time but only when debug is enabled.
I agree and would even go further: _PRS is optional and I don't think
there's a reason to log anything at all if it's absent. A log message
like "failed to evaluate _PRS" makes people think something is wrong
when in fact nothing is wrong.
That leads to the mindset of treating a missing _PRS as an error when
it's not. In fact, it looks like acpi_pci_link_add() *does* treat
this as an error. If _PRS doesn't exist, it skips the _CRS
evaluation. That seems wrong.
> Signed-off-by: Alex Hung <alex.hung@xxxxxxxxxxxxx>
> ---
> drivers/acpi/pci_link.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> index 85ad679..9d9cf24 100644
> --- a/drivers/acpi/pci_link.c
> +++ b/drivers/acpi/pci_link.c
> @@ -173,7 +173,7 @@ static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
> status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
> acpi_pci_link_check_possible, link);
> if (ACPI_FAILURE(status)) {
> - ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
> + acpi_handle_debug(link->device->handle, "failed to evaluate _PRS");
> return -ENODEV;
> }
>
> --
> 2.7.4
>
