Re: [PATCH v22 07/11] acpi/arm64: Add GTDT table parse driver

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Wed, Mar 29, 2017 at 05:48:17PM +0800, Fu Wei wrote:

[...]

>  * @platform_timer_count: It points to a integer variable which is used
>  *                           for storing the number of platform timers.
>  *                           This pointer could be NULL, if the caller
>  *                           doesn't need this info.
> 
> >
> >> + *
> >> + * Return: 0 if success, -EINVAL if error.
> >> + */
> >> +int __init acpi_gtdt_init(struct acpi_table_header *table,
> >> +                       int *platform_timer_count)
> >> +{
> >> +     int ret = 0;
> >> +     int timer_count = 0;
> >> +     void *platform_timer = NULL;
> >> +     struct acpi_table_gtdt *gtdt;
> >> +
> >> +     gtdt = container_of(table, struct acpi_table_gtdt, header);
> >> +     acpi_gtdt_desc.gtdt = gtdt;
> >> +     acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
> >> +
> >> +     if (table->revision < 2)
> >> +             pr_warn("Revision:%d doesn't support Platform Timers.\n",
> >> +                     table->revision);
> >
> > Ok, two points here. First, I am not sure why you should warn if the
> > table revision is < 2, is that a FW bug ? I do not think it is, you
> > can just return 0.
> 
> I used pr_debug here before v20, then I got Hanjun's suggestion:
> -------
> GTDT table revision is updated to 2 in ACPI 5.1, we will
> not support ACPI version under 5.1 and disable ACPI in FADT
> parse before this code is called, so if we get revision
> <2 here, I think we need to print warning (we need to keep
> the firmware stick to the spec on ARM64).
> -------
> https://lkml.org/lkml/2017/1/19/82
> 
> So I started to use pr_warn.

Thanks for the explanation, so it is a FW bug and the warning
is granted :) just leave it there.

Still, please check my comment on acpi_gtdt_init() being called
multiple times on patch 11.

Thanks,
Lorenzo