Re: ACPI regression in 2.6.25-rc6 (function keys stop working)

[Alexey Starikovskiy]

Hi Guillaume,

Please check if the patch to call _PSW methods, attached to bug #9998
helps to reduce number of ACPI interrupts if you revert the 2c81ce4c9c3

Thanks,
Alex.


Guillaume Chazarain wrote:
> Hi,
>
> There is an ACPI regression in 2.6.25-rc6, which causes the ACPI keys
> to stop working on my laptop, an Asus V6VA. git bisect identified the
> appended commit as guilty, and reverting it indeed fixes the problem
> for me. Attached are my .config, a good dmesg and a bad one. The diff
> between both dmesg reveals this interesting hunk:
>
> @@ -121,8 +121,9 @@
>  ACPI: (supports S0 S1 S3 S4 S5)
>  ACPI: Using IOAPIC for interrupt routing
>  ACPI: EC: non-query interrupt received, switching to interrupt mode
> +ACPI: EC: GPE storm detected, disabling EC GPE
>  ACPI: EC: GPE = 0x1c, I/O: command/status = 0x66, data = 0x62
> -ACPI: EC: driver started in interrupt mode
> +ACPI: EC: driver started in poll mode
>  ACPI: PCI Root Bridge [PCI0] (0000:00)
>  pci 0000:00:1f.0: Enabled ICH6/i801 SMBus device
>  pci 0000:00:1f.0: quirk: region 0800-087f claimed by ICH6 ACPI/GPIO/TCO
>
>
> Thanks.
>
>
> commit 2c81ce4c9c37b910210f2640c28e98a0c398dc26
> Author: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
> Date:   Tue Mar 11 13:30:00 2008 -0400
>
>     ACPI: EC: Handle IRQ storm on Acer laptops
>
>     On some Acer systems, the HW fails to clear the GPE source,
>     causing an interrupt storm.
>
>     So in EC interrupt mode, we count how many interrupts we
>     receive when waiting.  If we get more than 5, we give
>     up on interrupt mode and revert to polling mode.
>
>     Also, for polling mode to work on Acers, we need
>     to insert a delay.
>
>     Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
>     Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
>
> diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
> index caf873c..2c77359 100644
> --- a/drivers/acpi/ec.c
> +++ b/drivers/acpi/ec.c
> @@ -129,6 +129,7 @@ static struct acpi_ec {
>  	struct mutex lock;
>  	wait_queue_head_t wait;
>  	struct list_head list;
> +	atomic_t irq_count;
>  	u8 handlers_installed;
>  } *boot_ec, *first_ec;
>
> @@ -181,6 +182,8 @@ static int acpi_ec_wait(struct acpi_ec *ec, enum
> ec_event event, int force_poll)
>  {
>  	int ret = 0;
>
> +	atomic_set(&ec->irq_count, 0);
> +
>  	if (unlikely(event == ACPI_EC_EVENT_OBF_1 &&
>  		     test_bit(EC_FLAGS_NO_OBF1_GPE, &ec->flags)))
>  		force_poll = 1;
> @@ -227,6 +230,7 @@ static int acpi_ec_wait(struct acpi_ec *ec, enum
> ec_event event, int force_poll)
>  		while (time_before(jiffies, delay)) {
>  			if (acpi_ec_check_status(ec, event))
>  				goto end;
> +			msleep(5);
>  		}
>  	}
>  	pr_err(PREFIX "acpi_ec_wait timeout,"
> @@ -529,6 +533,13 @@ static u32 acpi_ec_gpe_handler(void *data)
>  	struct acpi_ec *ec = data;
>
>  	pr_debug(PREFIX "~~~> interrupt\n");
> +	atomic_inc(&ec->irq_count);
> +	if (atomic_read(&ec->irq_count) > 5) {
> +		pr_err(PREFIX "GPE storm detected, disabling EC GPE\n");
> +		acpi_disable_gpe(NULL, ec->gpe, ACPI_ISR);
> +		clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
> +		return ACPI_INTERRUPT_HANDLED;
> +	}
>  	clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
>  	if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))
>  		wake_up(&ec->wait);

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