Re: [BKPATCH] ACPI for 2.4

[Willy Tarreau]

Replying to myself...

On Sun, Feb 08, 2004 at 09:20:59AM +0100, Willy Tarreau wrote:
> 
> So I've added printk's into acpi_power_off(), and I see that the system
> doesn't return from acpi_enter_sleep_state_prep(S5), which itself hangs
> on the call to acpi_evaluate_object(NULL, "\\_PTS",...). If I comment
> out this line, it now goes on through the next calls, then normally leaves
> acpi_enter_sleep_state_prep(), then powers off correctly.

Searching for _PTS on google directed me to the ACPI spec. I found in
section 9 that _PTS (prepare to sleep) is only used for S1-S4, but 9.1.7
says that it should be called for S5 too. I suspect that depending on the
paragraph they read, hardware makers do or don't implement _PTS(S5) correctly
:-/ BTW, 9.1.5 says that "S5 is not a sleeping state, but a G2 state". So it
might seem logical not to call something named "prepare to sleep" in this
case.

I checked the last working version. It was acpi-030424 + the two little
patches I sent to you at this time and which were merged. This version
called _PTS and _GTS in acpi_enter_sleep_state_prep(), while now we call
_PTS, _GTS, and _SI._SST. So I'm amazed that in previous version, _PTS
worked and that it does not anymore !

Regards,
Willy

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