[PATCH]arm64: ignore FACS load failed for arm64

[Colin Ian King]

On 20/10/14 09:37, Fu Wei wrote:
> arm64: ignore load failed for FACS which is involved in old 
> BIOS style suspend/hibernate and does not make sense on arm64.
> 
> Signed-off-by: Fu Wei <fu.wei at linaro.org>
> ---
>  src/lib/src/fwts_acpi_tables.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/lib/src/fwts_acpi_tables.c b/src/lib/src/fwts_acpi_tables.c
> index 56498e0..0641d93 100644
> --- a/src/lib/src/fwts_acpi_tables.c
> +++ b/src/lib/src/fwts_acpi_tables.c
> @@ -375,7 +375,12 @@ static int fwts_acpi_handle_fadt(
>  	    "FACS", "FIRMWARE_CTRL", "X_FIRMWARE_CTRL",
>  	     &fadt->firmware_control, &fadt->x_firmware_ctrl,
>  	     provenance) != FWTS_OK) {
> +#if defined(__aarch64__)
> +		fwts_log_warning(fw, "Failed to load FACS: Cannot determine "
> +				"address of FACS from FADT. IGNORE for AArch64 platform!");
> +#else
>  		return FWTS_ERROR;
> +#endif
>  	}
>  	/* Determine DSDT addr and load it */
>  	if (fwts_acpi_handle_fadt_tables(fw, fadt,
> 

I've re-read the relevant sections of the ACPI 5.1 specification and I
can't see any mention of this table being mandatory or not; so a failure
on it not existing may be wrong for any architecture.

Does the Fixed ACPI Description Table Fixed Feature Flags
HW_REDUCED_ACPI bit being set to 1 imply that the FACS not existing is
OK?  (See ACPI 5.1, able 5-35, bit 20).

If that is a reasonable assumption, maybe that would be a better way of
checking. E.g.

diff --git a/src/lib/src/fwts_acpi_tables.c b/src/lib/src/fwts_acpi_tables.c
index 56498e0..97a7bd4 100644
--- a/src/lib/src/fwts_acpi_tables.c
+++ b/src/lib/src/fwts_acpi_tables.c
@@ -311,6 +311,9 @@ static int fwts_acpi_handle_fadt_tables(
                }
                /* Is it sane? */
                if (addr == 0) {
+                       /* HW_REDUCED - address can be zero */
+                       if (fadt->flags & (1 << 20))
+                               return FWTS_OK;
                        fwts_log_error(fw, "Failed to load %s: Cannot
determine "
                                "address of %s from FADT, fields %s and
%s are zero.",
                                name, name, name_addr32, name_addr64);
@@ -320,6 +323,9 @@ static int fwts_acpi_handle_fadt_tables(
                addr = (off_t)*addr32;
                /* Is it sane? */
                if (addr == 0)  {
+                       /* HW_REDUCED - address can be zero */
+                       if (fadt->flags & (1 << 20))
+                               return FWTS_OK;
                        fwts_log_error(fw, "Failed to load %s: Cannot
determine "
                                "address of %s from FADT, field %s is
zero.",
                                name, name, name_addr32);


Colin