Re: [PATCH] ACPI:remove panic in case hardware has changed after S4

[joeyli <jlee@suse.com>]

於 四，2013-07-11 於 14:14 +0200，oliver@neukum.org 提到：
> From: Oliver Neukum <oneukum@suse.de>
> 
> Some BIOSes change hardware based on the state of
> a laptop's lid. If the lid is closed, the touchpad is
> disabled and the checksum changes.
> 
> Signed-off-by: Oliver Neukum <oneukum@suse.de>
> ---
>  drivers/acpi/sleep.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> index 9c1a435..14744e5 100644
> --- a/drivers/acpi/sleep.c
> +++ b/drivers/acpi/sleep.c
> @@ -664,11 +664,9 @@ static void acpi_hibernation_leave(void)
>  	/* Reprogram control registers */
>  	acpi_leave_sleep_state_prep(ACPI_STATE_S4);
>  	/* Check the hardware signature */
> -	if (facs && s4_hardware_signature != facs->hardware_signature) {
> -		printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
> -			"cannot resume!\n");
> -		panic("ACPI S4 hardware signature mismatch");
> -	}
> +	if (facs && s4_hardware_signature != facs->hardware_signature)
> +		printk(KERN_CRIT "ACPI: Hardware changed while hibernated, "
> +			"success doubtful!\n");

This panic is also reflect to the memory size changed by user when
machine in S4 state, BIOS should update hardware_signature to raise
memory changed.

Does it a good idea don't panic here if memory size changed?

Should we need try to detect the change of memory or touchpad for know
should we panic or not?

>  	/* Restore the NVS memory area */
>  	suspend_nvs_restore();
>  	/* Allow EC transactions to happen. */

On the other hand, I saw another BIOS changed hardware_signature because
the VGA detect output resolution changed when S4 resume. It's a problem
for sometimes BIOS widely used hardware_signature on non-critical
hardware change.


Thanks a lot!
Joey Lee

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