On 12/05/2007, Linus Torvalds <[email protected]> wrote:
>
>
> On Fri, 11 May 2007, Rafael J. Wysocki wrote:
> >
> > We're working on fixing the breakage, but currently it's difficult, because
> > none of my testboxes has problems with the 'platform' hibernation and I
> > cannot reproduce the reported issues.
>
> The rule for anything ACPI-related has been: no regressions.
>
> It doesn't matter if something fixes 10 boxes, if it breaks a single one,
> it's going to get reverted.
>
> We had much too much of the "two steps forward, one step back" dance with
> ACPI a few years ago, which is the reason that rule got installed (and
> which is why it's ACPI-only: in some other subsystems we accept the fact
> that sometimes we don't know how to fix some hardware issue, but the new
> situation is at least better than the old one).
>
> I agree that it can be aggravating to know that you can fix a problem for
> some people, but then being limited by the fact that it breaks for others.
> But beign able to *rely* on something that used to work is just too
> important, and with ACPI, you can never make a good judgement of which way
> works better (since it really just depends on some random firmware issues
> that we have zero visibility into).
>
> Also, quite often, it may *seem* like something fixes more boxes than it
> breaks, but it's because people report *breakage* only, and then a few
> months later it turns out that it's exactly the other way around: now it's
> a hundred people who report breakage with the *new* code, and the reason
> people thought it fixed more than it broke was that the people for whom
> the old code worked fine obviously never reported it!
>
> So this is why "a single regression is considered more important than ten
> fixes" - because a single regressionr report tends to actually be just the
> first indication of a lot of people who simply haven't tested the new code
> yet! People for whom the old code is broken are more likely to test new
> things.
>
> So I'd just suggest changing the default back to PM_DISK_SHUTDOWN (but
> leave the "pm_ops->enter" testing in place - ie not reverting the other
> commits in the series).
>
> The patch would look something like this. Coywolf, does this fix it for
> you?
>
Yes, it fixes my problem.
(Sorry for this long delayed report. I didn't get the chance to test
and reboot my box.)
This quick test explains me the problem that we should not set
hibernation_mode to HIBERNATION_PLATFORM if it is not !ops". I will
post a formal patch later.
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index eb72255..8e52553 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -62,7 +62,7 @@ void hibernation_set_ops(struct hibernation_ops *ops)
mutex_lock(&pm_mutex);
hibernation_ops = ops;
if (ops)
- hibernation_mode = HIBERNATION_PLATFORM;
+ ;
else if (hibernation_mode == HIBERNATION_PLATFORM)
hibernation_mode = HIBERNATION_SHUTDOWN;
> Linus
>
> ---
> kernel/power/disk.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/power/disk.c b/kernel/power/disk.c
> index b5f0543..f6aa06e 100644
> --- a/kernel/power/disk.c
> +++ b/kernel/power/disk.c
> @@ -60,9 +60,9 @@ void hibernation_set_ops(struct hibernation_ops *ops)
> }
> mutex_lock(&pm_mutex);
> hibernation_ops = ops;
> - if (ops)
> - hibernation_mode = HIBERNATION_PLATFORM;
> - else if (hibernation_mode == HIBERNATION_PLATFORM)
> +
> + /* Turn off HIBERNATION_PLATFORM if we no longer have any platform ops */
> + if (!ops && hibernation_mode == HIBERNATION_PLATFORM)
> hibernation_mode = HIBERNATION_SHUTDOWN;
>
> mutex_unlock(&pm_mutex);
>
--
Qi Yong
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