Re: [RFC][RFT][PATCH] ACPI: Protection from suspending in the middle of EC transaction

[Alan Jenkins]

On 1/30/10, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> Hi,
>
> While Maxim is testing if the patch below helps with
> http://bugzilla.kernel.org/show_bug.cgi?id=14668
> I think it's necessary anyway.
>
> The problem is that currently there's nothing to prevent us from suspending
> in
> the middle of an EC transaction in progress, at least as far as I can see.
> As a result, we can suspend with the ACPI global lock held or something like
> this, which leads to problems especially for hibernation (if the resume
> kernel
> passes control to the image kernel in the middle of an EC transaction,
> things
> aren't nice).  For this reason I think we should wait until there are no EC
> transactions in progress before we suspend and we should prevent any new
> EC transactions from starting after that point.  The patch below does that.

I also believe this is a problem.  I reported the following -

<http://bugzilla.kernel.org/show_bug.cgi?id=14112> "Pressing acpi
hotkeys duing hibernation may occasionally cause EC transaction
timeout"

and posted a patch, but I couldn't reproduce my specific issue in
order to confirm that the patch helped.

Regards
Alan
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