I have not seen any ACPI errors other than during suspend/resume.

Tried ec_intr=0 option on the command line, same problem.

ACPI_EC_DELAY=100 patch did not help either, same or at least similar 
problem. Output attached.

Yu, Luming wrote:
>> No luck with 2.6.16-rc3. Slightly different messages, but still ACPI 
>> complaints about EC, battery status polling fails and the 
>> keyboard loses 
>> characters after resume. Full dmesg attached.
>>
> Do you have such issues before resume?
> What about ec_intr=0?
> 
> I found "ACPI: read EC, IB not empty" in the dmesg.
> Could you try this against 2.6.16-rc3
> 
> diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
> index 79b09d7..c4c9ded 100644
> --- a/drivers/acpi/ec.c
> +++ b/drivers/acpi/ec.c
> @@ -51,7 +51,7 @@ ACPI_MODULE_NAME("acpi_ec")
>  #define ACPI_EC_FLAG_SCI       0x20    /* EC-SCI occurred */
>  #define ACPI_EC_EVENT_OBF      0x01    /* Output buffer full */
>  #define ACPI_EC_EVENT_IBE      0x02    /* Input buffer empty */
> -#define ACPI_EC_DELAY          50      /* Wait 50ms max. during EC ops
> */
> +#define ACPI_EC_DELAY          100     /* Wait 50ms max. during EC ops
> */
>  #define ACPI_EC_UDELAY_GLK     1000    /* Wait 1ms max. to get global
> lock */
>  #define ACPI_EC_UDELAY         100     /* Poll @ 100us increments */
>  #define ACPI_EC_UDELAY_COUNT   1000    /* Wait 10ms max. during EC ops
> */
>