Messages in this thread Patch in this message |  | | Subject | Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier | From | Dou Liyang <> | Date | Mon, 31 Jul 2017 18:50:38 +0800 |
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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.
[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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