On Thu, 7 Jan 2010, Christian Hofstaedtler wrote:
Thanks for writing this patch Christian,
it is something that has been unsettled for
a long time and it will be great to close the issue.
> Newer hardware is assumed to no longer reboot succesfully using the
> keyboard controller, but needs to use ACPI instead.
> To not cause problems with older hardware, only hardware with a BIOS
> date 2006 or newer is considered for this choice. Broken BIOSes
> reporting a BIOS date of 0 are not specially considered, and therefore
> get the KBD reboot behaviour.
>
> Also unifiy reboot_type selection code.
Please split the patch in two patches:
1. cleanup w/o policy change
2. policy change w/o cleanup
better if the policy change is #2, so if we need to revert it
we don't have to revert the cleanup too.
> Signed-off-by: Christian Hofstaedtler <ch@xxxxxxx>
> ---
> arch/x86/include/asm/emergency-restart.h | 1 +
> arch/x86/kernel/reboot.c | 65 ++++++++++++++++++++++++------
> 2 files changed, 53 insertions(+), 13 deletions(-)
> +/* See if the Hardware is new enough to support ACPI reboots. */
> +static int __init reboot_acpi_likey_supported(void)
> +{
> + int year;
> +
> + /* Doesn't exist? Likely an old system */
> + if (!dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL)) {
> + return 0;
> + }
I think it may be better to simply return 1 in this case.
While we have seen dmi_get_date() fail in practice on "modern" machines,
if CONFIG_ACPI_BLACKLIST_YEAR is set, we will already punish users by
disabling ACPI and making them invoke acpi=force.
So the effect of this check is to disable ACPI-reset
on systems where the user has likely already invoked acpi=force --
which seems somewhat counter-intuitive.
> + /* 2006 was decided as the cut-off year. */
> + if (year < 2006) {
> + return 0;
> + }
I'd rather see 2003.
If we run into trouble, it is a 1-liner to move it forward.
But I think we'll probably do fine with anything newer than 2001.
thanks,
Len Brown, Intel Open Source Technolgy Center
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