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Date: Thu, 24 Aug 2017 11:54:28 +0800 From: Dou Liyang <douly.fnst@...fujitsu.com> To: <x86@...nel.org>, <linux-kernel@...r.kernel.org>, "Rafael J. Wysocki" <rjw@...ysocki.net>, "Zheng, Lv" <lv.zheng@...el.com> CC: <tglx@...utronix.de>, <mingo@...nel.org>, <hpa@...or.com>, <ebiederm@...ssion.com>, <bhe@...hat.com>, <peterz@...radead.org>, <izumi.taku@...fujitsu.com>, <tokunaga.keiich@...fujitsu.com>, <linux-acpi@...r.kernel.org>, Julian Wollrath <jwollrath@....de>, Borislav Petkov <bp@...en8.de> Subject: Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier 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@...el.com> >> Signed-off-by: Dou Liyang <douly.fnst@...fujitsu.com> >> Cc: linux-acpi@...r.kernel.org >> Cc: Rafael J. Wysocki <rjw@...ysocki.net> >> Cc: Zheng, Lv <lv.zheng@...el.com> >> Cc: Julian Wollrath <jwollrath@....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. Thanks, dou. > [1] https://lkml.org/lkml/2014/3/10/123 > [2] https://lkml.org/lkml/2014/3/12/311 > > > Thanks > dou. > >> init/main.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/init/main.c b/init/main.c >> index df58a41..7a09467 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -654,12 +654,12 @@ asmlinkage __visible void __init start_kernel(void) >> kmemleak_init(); >> setup_per_cpu_pageset(); >> numa_policy_init(); >> + acpi_early_init(); >> if (late_time_init) >> late_time_init(); >> calibrate_delay(); >> pidmap_init(); >> anon_vma_init(); >> - acpi_early_init(); >> #ifdef CONFIG_X86 >> if (efi_enabled(EFI_RUNTIME_SERVICES)) >> efi_enter_virtual_mode(); >>
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