On Wed, Jan 10, 2007 at 01:00:53PM +0900, YONETANI Tomokazu wrote:
[spinlock remains held for no reason]
> From the debugging output, I know the spinlock holder is always
> the line 592 of AcpiHwReadRegister(), and the only caller of this function
> with ACPI_MTX_LOCK is AcpiRegisterRead() in AcpiEnterSleepState():
>
> /* Wait until we enter sleep state */
>
> do
> {
AcpiOsStall(1000); <== INSERT THIS
> Status = AcpiGetRegister (ACPI_BITREG_WAKE_STATUS, &InValue);
> if (ACPI_FAILURE (Status))
> {
> return_ACPI_STATUS (Status);
> }
>
> /* Spin until we wake */
>
> } while (!InValue);
While looking around, I found that AcpiEnterSleepStateS4Bios() has
similar spin loop at the bottom, but with a call to AcpiOsStall()
(== DELAY()) before AcpiGetRegister(). So I tried adding it to
AcpiEnterSleepState() too, and to my amazement, the problem went away.
I tried several ten times of suspending and waking up the laptop,
but I'm no longer able to reproduce it. My question, though, is why
why just a DELAY() makes any difference (ISTR making gd_spinlocks_wr
volatile didn't solve the problem).
Anyway, new version is here:
http://les.ath.cx/DragonFly/acpi-20061109-19.diff
Cheers.
