Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Friday, August 25, 2017 4:06:11 AM CEST Dou Liyang wrote:
> Hi Rafael,
> 
> At 08/25/2017 12:38 AM, Rafael J. Wysocki wrote:
> > On Thursday, August 24, 2017 5:54:28 AM CEST Dou Liyang wrote:
> >> Hi Rafael, Zheng,
> >>
> >> At 07/31/2017 06:50 PM, Dou Liyang wrote:
> >>> Hi,
> >>>
> >>> At 07/14/2017 01:52 PM, Dou Liyang wrote:
> >>>> Linux uses acpi_early_init() to put the ACPI table management into
> >>>> the late stage from the early stage where the mapped ACPI tables is
> >>>> temporary and should be unmapped.
> >>>>
> >>>> But, now initializing interrupt delivery mode should map and parse the
> >>>> DMAR table earlier in the early stage. This causes an ACPI error when
> >>>> Linux reallocates the ACPI root tables. Because Linux doesn't unmapped
> >>>> the DMAR table after using in the early stage.
> >>>>
> >>>> Invoke acpi_early_init() earlier before late_time_init(), Keep the DMAR
> >>>> be mapped and parsed in late stage like before.
> >>>>
> >>>> Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
> >>>> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> >>>> Cc: linux-acpi@vger.kernel.org
> >>>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> >>>> Cc: Zheng, Lv <lv.zheng@intel.com>
> >>>> Cc: Julian Wollrath <jwollrath@web.de>
> >>>> ---
> >>>> Test in my own PC(Lenovo M4340).
> >>>> Ask help for doing regression testing for the bug said in commit
> >>>> c4e1acbb35e4
> >>>> ("ACPI / init: Invoke early ACPI initialization later").
> >>>>
> >>>
> >>> Now, I can prove this patch doesn't result in the bug[1] which made the
> >>> fast TSC calibration using PIT failed in a Thinkpad x121e (AMD E-450
> >>> APU).
> >>>
> >>> The true reason of the bug is enabling ACPI subsystem earlier than
> >>> using PIT, not the SCI setup. invoking acpi_enable_subsystem() later
> >>> could fix this bug as Julian tested and said[2].
> >>>
> >>> And, I found that Commit b064a8fa77df (" ACPI / init: Switch over
> >>> platform to the ACPI mode later") split the ACPI early initialization
> >>> code into acpi_early_init() and acpi_subsystem_init(). executing
> >>> acpi_enable_subsystem() at the original early ACPI initialization spot.
> >>>
> >>> The sequence of them shows below:
> >>>
> >>>  start_kernel
> >>> +---------------+
> >>> |
> >>> +--> .......
> >>> |
> >>> |    late_time_init()
> >>> +--> +-------+
> >>> |
> >>> +--> .......
> >>> |
> >>> |    acpi_early_init()
> >>> +--> +-------+
> >>> |
> >>> +--> .......
> >>> |
> >>> |   acpi_subsystem_init()
> >>> +-> +--------+
> >>>
> >>> We make sure the acpi_subsystem_init() is called later than
> >>> late_time_init(), the bug will be avoided.
> >>>
> >>> This patch changes the sequence of late_time_init() and
> >>> acpi_early_init(), doesn't effect acpi_subsystem_init().
> >>>
> >>> So, this patch is OK.
> >>>
> >>> Btw, Thanks very much for Borislav Petkov, he will have access to
> >>> Thinkpad x121e from Mid-August and will test this series.
> >>>
> >>
> >> Almost one month passed, Borislav have tested this series in Thinkpad
> >> x121e and I also have tested in my box and QEmu again. It is OK.
> >>
> >> BTW,
> >> 1) I found your commit b064a8fa77df (" ACPI / init: Switch over
> >> platform to the ACPI mode later") split the ACPI early initialization
> >> code into acpi_early_init() and acpi_subsystem_init(). Actually enabling
> >> the ACPI subsystem is in acpi_subsystem_init().
> >>
> >> 2) As we discussed earlier, invoking acpi_put_table() is not good for
> >> this situation.
> >>
> >> So I do this patch, Is that goot to you? Any comments will be welcome.
> >>
> >> If it is OK, As the patches need to be re-based, and I also found
> >> several spelling mistake, I will send a new version next week.
> >
> > OK, but does it depend on anything?  Or does anything depend on it?
> >
> 
> It depends on nothing and can be considered independent.

OK

Please send it as an independent patch, then.

> [11/13] patch in this series depends on it. [11/13] patch caused an
> ACPI error, we used this patch to fix it.

So the ordering of patches in the series should be different, then.

It should be ordered so as to avoid triggering the warning at all,
so this patch should go before the [11/13].

> > It is [12/13] in a series, so it looks like it doesn't depend on the
> > previous patches in it, but the next one may depend on it?  Which is the
> > case?
> >
> 
> The second case(the next one may depend on it) is what I want.
> 
> But, seems I made a mistake about the order of the patches. I should
> put it before [11/13] to avoid the ACPI error.

Right.

> I will adjust the order of the patches in the next version, and post
> the whole series to you.

Please just CC it to linux-acpi.

Thanks,
Rafael