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From: hasyed on 5 Aug 2010 16:26
From my windows user-mode environment, I would like to read the temperature
of the thermal zones. I don't want to use WMI since those values are not
updated on most systems. I would like to use IOCTL_ACPI_EVAL_METHOD.

Using device manager, I see that the thermal zones don't really have a
driver associated with them. Nevertheless, I tried the following code below.

I am able to get a handle to the thermal zone using CreateFile

hDevice = CreateFile(szDevicePath, (DWORD)(GENERIC_READ | GENERIC_WRITE), 0,
NULL,OPEN_EXISTING,0,NULL);

if (hDevice == INVALID_HANDLE_VALUE)
{
return 0;
}

InBuf.Signature = ACPI_EVAL_INPUT_BUFFER_SIGNATURE;
InBuf.MethodName[0] = '_';
InBuf.MethodName[1] = 'T';
InBuf.MethodName[2] = 'M';
InBuf.MethodName[3] = 'P';

// Verify Driver version from driver
IoctlResult = DeviceIoControl(hDevice,
IOCTL_ACPI_EVAL_METHOD,
&InBuf, (DWORD) sizeof(InBuf), // Input
&OutBuff, (DWORD) sizeof(OutBuff), //
Output
&ReturnedLength,
NULL);

The IoctlResult in Vista returns a 1 and the OutBuff contains junk data. In
XP, IoctlResult is a 0 (fail).

To get the handle to the thermal zone, I used functions SetupDiGetClassDevs,
SetupDiEnumDeviceInterfaces, SetupDiGetDeviceInterfaceDetail with the
thermalzone guid.

Am I on the right path? What am I missing?

Thanks for any guidance.
From: Maxim S. Shatskih on 6 Aug 2010 02:29
> From my windows user-mode environment, I would like to read the temperature
> of the thermal zones. I don't want to use WMI since those values are not
> updated on most systems. I would like to use IOCTL_ACPI_EVAL_METHOD.

Well, if WMI is not implemented, then probably the ACPI thermal zones are also non-working.

--
Maxim S. Shatskih
Windows DDK MVP
maxim(a)storagecraft.com
http://www.storagecraft.com

From: hasyed on 6 Aug 2010 10:00
WMI is implemented. On a number of systems, if you use WMI to read the
thermal zone temperature, you will see the temperature does not change. Or it
won't change as regularly as you would like. Perhaps, the BIOS team decided
to only update through WMI once every 3 minutes.

So, if one want to read the thermal zone temperature every 5 seconds, one
can't go through WMI. One has to somehow evaluate the ACPI method (_TMP) that
is associated with a particular thermal zone.

From: hasyed on 6 Aug 2010 11:10
I don't know what happened to another reply that I made. Below is what I
tried to ask in that.

Part of my question is, "Do I need to build a driver for a particular
thermal zone" and then issue an IOCTL call (IOCTL_ACPI_EVAL_METHOD) to that
particular driver? In the msdn, it mentions, "To enhance the functionality of
an ACPI device, the vendor can supply a WDM function driver, which
communicates with the ACPI BIOS through an operation region supplied by the
driver"

Since I don't want to enhance the ACPI device, I assume that I don't need to
build a driver. I can just use CreateFile to get a handle to that device and
issue an IOCTL call.

Please correct me if I am wrong on this.

Thanks
From: Doron Holan [MSFT] on 6 Aug 2010 13:24
you cannot send this IOCTL from user mode, the driver will not process it

"hasyed" wrote in message
news:B0870B4E-51EA-4310-95DA-C2081761F270(a)microsoft.com...

I don't know what happened to another reply that I made. Below is what I
tried to ask in that.

Part of my question is, "Do I need to build a driver for a particular
thermal zone" and then issue an IOCTL call (IOCTL_ACPI_EVAL_METHOD) to that
particular driver? In the msdn, it mentions, "To enhance the functionality
of
an ACPI device, the vendor can supply a WDM function driver, which
communicates with the ACPI BIOS through an operation region supplied by the
driver"

Since I don't want to enhance the ACPI device, I assume that I don't need to
build a driver. I can just use CreateFile to get a handle to that device and
issue an IOCTL call.

Please correct me if I am wrong on this.

Thanks

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