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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 9 Jul 2018 23:28:47 +0200
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Subject: Re: 4.18rc3 TX2 boot failure with "ACPICA: AML parser: attempt to
 continue loading table after error"
To:     Jeremy Linton <jeremy.linton@arm.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        "Schmauss, Erik" <erik.schmauss@intel.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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On Mon, Jul 9, 2018 at 10:45 PM, Jeremy Linton <jeremy.linton@arm.com> wrote:
> Hi,
>
> First thanks for the patch..
>
> On 07/08/2018 04:14 AM, Rafael J. Wysocki wrote:
>>
>> On Monday, July 2, 2018 11:41:42 PM CEST Jeremy Linton wrote:
>>>
>>> Hi,
>>>
>>> I'm experiencing two problems with commit 5088814a6e931 which is
>>> "ACPICA: AML parser: attempt to continue loading table after error"
>>>
>>> The first is this boot failure on a thunderX2:
>>>
>>> [   10.770098] ACPI Error: Ignore error and continue table load
>
>
> [trimming]
>
>>> ]---
>>>
>>> Which does appear to be the result of some bad data in the table, but it
>>> was working with 4.17, and reverting this commit solves the problem.
>>
>>
>> Does the patch below make any difference?
>>
>> ---
>>   drivers/acpi/acpica/psobject.c |    3 +++
>>   1 file changed, 3 insertions(+)
>>
>> Index: linux-pm/drivers/acpi/acpica/psobject.c
>> ===================================================================
>> --- linux-pm.orig/drivers/acpi/acpica/psobject.c
>> +++ linux-pm/drivers/acpi/acpica/psobject.c
>> @@ -39,6 +39,9 @@ static acpi_status acpi_ps_get_aml_opcod
>>         ACPI_FUNCTION_TRACE_PTR(ps_get_aml_opcode, walk_state);
>>         walk_state->aml = walk_state->parser_state.aml;
>> +       if (!walk_state->aml)
>> +               return AE_CTRL_PARSE_CONTINUE;
>> +
>
>
> Well this seems to avoid the crash, but now it hangs right after on the
> "Ignore error and continue table load" message.

Well, maybe we should just abort in that case.

I'm wondering what happens if you replace the return statement in the
patch above with

return_ACPI_STATUS(AE_AML_BAD_OPCODE)


> I would post the DSDT but
> I'm borrowing this machine, and I understand the firmware to be an early
> release, so...

Please send the output of acpidump from it to Erik in private.  That
will help him and Bob to make the code more robust.

> Anyway, now that I have access again, i'm turning up the debug messaging,
> let me see if that points at whats causing the hang.

OK, thanks!