Re: Problem: ACPI related soft lockup on Fujitsu-Siemens AMILO Si 2636

[Alexey Starikovskiy <aystarik@gmail.com>]

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Alexey Starikovskiy wrote:
> Thomas Lindroth wrote:
>> I've done some debugging of this problem myself and reached some 
>> conclusions.
>>
>> I tried activating the ACPI_LV_INFO ACPI debug mode and observed what 
>> happens
>> when the system is under load. I saved one trace and put it in the file
>> acpi_debug_log at http://www.cyd.liu.se/~tholi945/acpi-bug-2008-10-06/
>>
>> When the temp goes over the ACPI passive trip point the processor gets
>> throttled. It usually never goes over T4 before the temp falls below the
>> passive temp but sometimes it reaches the highest T7. If it reach T7 the
>> next call to _TMP or _L18 never returns. I've confirmed this by running
>> echo T7 > /proc/acpi/processor/CPU*/throttling and then tried to read
>> from /proc/acpi/thermal_zone/TZ00/temperature and it fails in the 
>> same way.
>>
>> I've tried activating the ACPI_LV_PARSE ACPI debug mode, enter T7 and 
>> read
>> from temp. I put the result of that in the trace_debug file at the 
>> same adress.
>>
>> The AML call chain looks like this _TMP -> PMRD -> RCMD -> WIBF
>> WIBF always returns 1 causing the interpreter to get stuck in the while
>> loop in PMRD.
>>
>> While (RCMD (0x80, Local0))
>> {
>>     Noop
>>     Noop
>>     Store (PMUC, Local5)
>>     If (And (Local5, One, Local2))
>>     {
>>         Store (PMUD, Local5)
>>     }
>> }
>>
>>   
> This is AML implementation of EC driver... it relies on certain speed
> of AML interpreter to work properly (look for Noop inserted as delay).
>
> It is possible to replace this driver with the native Linux one, which 
> might be
> more robust, but this involves heavy DSDT hacking.
>
> Overall, it is heavily mis-designed BIOS, so don't expect it to be 
> fixed on Linux side.
>
> Regards,
> Alex.
Please check if making Noop a small delay helps





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diff --git a/drivers/acpi/dispatcher/dsopcode.c b/drivers/acpi/dispatcher/dsopcode.c
index 6a81c44..acd5fb6 100644
--- a/drivers/acpi/dispatcher/dsopcode.c
+++ b/drivers/acpi/dispatcher/dsopcode.c
@@ -1368,6 +1368,7 @@ acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state,
 	case AML_NOOP_OP:
 
 		/* Just do nothing! */
+		udelay(100);
 		break;
 
 	case AML_BREAK_POINT_OP: