The Zana Zen

Hi,

Here are some tips about debugging Windows ACPI DSDT/ASL using windbg.

Installing the checked version of acpi.sys

You need to get the checked version of acpi.sys by downloading the checked version of your service pack, then unpack it locally and expand the acpi._sy file (it is actually a .cab file). The checked version will let you use the amli debugger in order to trace and step through ASL code.

Tracing ACPI ASL Code and Object evaluation

!amli set traceon spewon verboseon – This is a bit slow but produces a nice log file (for real man only).

ASL Debug Print

If you can change the code (dump and disassemble the DSDT and then compile and embed it again), you can add some string outputs to the ASL code, you can do that by two ways, if you connect a debugger then use the simple method of storing a string into the Debug local variable (example below), the other way is to use my asl print function which prints to an io port of your choice, this is not useful if you are not a platform developer or use a virtual machine.

Examples:

Store (“Debug asl print example – 1″, Debug)
\ZDBG (“Debug asl print example – 1″)

Break Points

• If you want to debug ASL code, you can set breakpoints with !amli bp
• You can embed a breakpoint by changing the DSDT and put the BreakPoint directive in the ASL code where you want the debugger to break.

After you broke onto the amli debugger, you can trace and step() through the code.

This entry was posted on Monday, August 4th, 2008 at 2:50 pm and is filed under lowlevel, programming. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.