Re: 2.6.16-rc5: known regressions [TP 600X S3, vanilla DSDT]

[Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk>]

> So, please try hack thermal.c by removing calls to _TMP.

I did something like that before, by changing acpi_evaluate_integer()
to return 3000 if it is asked for _TMP.  

--- a/utils.c	2006-03-15 01:42:34.000000000 -0500
+++ b/utils.c	2006-03-14 23:36:59.000000000 -0500
@@ -270,7 +270,15 @@ acpi_evaluate_integer(acpi_handle handle
 	memset(element, 0, sizeof(union acpi_object));
 	buffer.length = sizeof(union acpi_object);
 	buffer.pointer = element;
-	status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
+	if (strcmp(pathname, "_TMP") != 0)
+	  status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
+	else {
+	  printk(KERN_INFO PREFIX "acpi_evaluate_integer: Faking _TMP\n");
+	  status = AE_OK;
+	  element->type = ACPI_TYPE_INTEGER;
+	  element->integer.value = 3000; /* 27 C, in deciKelvins */
+	}
+
 	if (ACPI_FAILURE(status)) {
 		acpi_util_eval_error(handle, pathname, status);
 		return_ACPI_STATUS(status);


The alternative, obvious change in thermal.c (diff below) turns out
not to be a minimal change.  If acpi_thermal_get_temperature() returns
with a failure, then most of the later methods in THM0 aren't
executed, so one is actually commenting out much more than _TMP.

Which is why I think the minimal change is the diff above to utils.c.
With that change the system never hung.

Or should I do a compromise modification, where calls from thermal.c
to _TMP use the hacked acpi_evaluate_integer()
[e.g. acpi_evaluate_integer_called_from_thermal()], but other calls to
_TMP get the unhacked version?

Here is the diff for commenting out _TMP directly in thermal.c, which
I think I've tried already but I'll try it again.  I'm sure it'll
work, though.

--- a/thermal.c	2006-03-16 09:45:30.000000000 -0500
+++ b/thermal.c	2006-03-17 09:00:30.000000000 -0500
@@ -222,7 +222,7 @@ static int acpi_thermal_get_temperature(
 
 	ACPI_FUNCTION_TRACE("acpi_thermal_get_temperature");
 
-	if (!tz)
+	if (!tz || strcmp(tz->handle, "_TMP") == 0)
 		return_VALUE(-EINVAL);
 
 	tz->last_temperature = tz->temperature;


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