Re: [PATCH v22 07/11] acpi/arm64: Add GTDT table parse driver
From: Lorenzo Pieralisi
Date: Wed Mar 29 2017 - 06:21:00 EST
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