Re: [PATCH 1/1] x86/acpi: Use FADT flags to determine the PMTMR width

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.06.2020 16:36, Grzegorz Uriasz wrote:
> --- a/xen/arch/x86/acpi/boot.c
> +++ b/xen/arch/x86/acpi/boot.c
> @@ -480,7 +480,10 @@ static int __init acpi_parse_fadt(struct 
> acpi_table_header *table)
>               if (fadt->xpm_timer_block.space_id ==
>                   ACPI_ADR_SPACE_SYSTEM_IO) {
>                       pmtmr_ioport = fadt->xpm_timer_block.address;
> -                     pmtmr_width = fadt->xpm_timer_block.bit_width;
> +                     if (fadt->flags & ACPI_FADT_32BIT_TIMER)
> +                             pmtmr_width = 32;
> +                     else
> +                             pmtmr_width = 24;

I think disagreement of the two wants logging, and you want to
default to using the smaller of the two (or even to ignoring the
timer altogether). Then there wants to be a way to override
(unless we already have one) our defaulting, in case it's wrong.

Also I'd prefer if you used a conditional operator for this
assignment.

Jan