acpi-debug.html

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partition. You can get a backtrace in <acronym class="ACRONYM">DDB</acronym> with <var
class="OPTION">tr</var>. If you have to handwrite the backtrace, be sure to at least get
the lowest five (5) and top five (5) lines in the trace.</p>

<p>Then, try to isolate the problem by booting with <acronym
class="ACRONYM">ACPI</acronym> disabled. If that works, you can isolate the <acronym
class="ACRONYM">ACPI</acronym> subsystem by using various values of <var
class="OPTION">debug.acpi.disable</var>. See the <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpi</span>(4)</span> manual page for some examples.</p>
</div>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN17069" name="AEN17069">11.16.3.4. System Powers Up After
Suspend or Shutdown</a></h3>

<p>First, try setting <var class="OPTION">hw.acpi.disable_on_poweroff=</var>``0'' in
<span class="CITEREFENTRY"><span class="REFENTRYTITLE">loader.conf</span>(5)</span>. This
keeps <acronym class="ACRONYM">ACPI</acronym> from disabling various events during the
shutdown process. Some systems need this value set to ``1'' (the default) for the same
reason. This usually fixes the problem of a system powering up spontaneously after a
suspend or poweroff.</p>
</div>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN17079" name="AEN17079">11.16.3.5. Other Problems</a></h3>

<p>If you have other problems with <acronym class="ACRONYM">ACPI</acronym> (working with
a docking station, devices not detected, etc.), please email a description to the mailing
list as well; however, some of these issues may be related to unfinished parts of the
<acronym class="ACRONYM">ACPI</acronym> subsystem so they might take a while to be
implemented. Please be patient and prepared to test patches we may send you.</p>
</div>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="ACPI-ASLANDDUMP" name="ACPI-ASLANDDUMP">11.16.4. <acronym
class="ACRONYM">ASL</acronym>, <tt class="COMMAND">acpidump</tt>, and <acronym
class="ACRONYM">IASL</acronym></a></h2>

<p>The most common problem is the <acronym class="ACRONYM">BIOS</acronym> vendors
providing incorrect (or outright buggy!) bytecode. This is usually manifested by kernel
console messages like this:</p>

<pre class="SCREEN">
ACPI-1287: *** Error: Method execution failed [\\_SB_.PCI0.LPC0.FIGD._STA] \\
(Node 0xc3f6d160), AE_NOT_FOUND
</pre>

<p>Often, you can resolve these problems by updating your <acronym
class="ACRONYM">BIOS</acronym> to the latest revision. Most console messages are harmless
but if you have other problems like battery status not working, they're a good place to
start looking for problems in the <acronym class="ACRONYM">AML</acronym>. The bytecode,
known as <acronym class="ACRONYM">AML</acronym>, is compiled from a source language
called <acronym class="ACRONYM">ASL</acronym>. The <acronym class="ACRONYM">AML</acronym>
is found in the table known as the <acronym class="ACRONYM">DSDT</acronym>. To get a copy
of your <acronym class="ACRONYM">ASL</acronym>, use <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpidump</span>(8)</span>. You should use both the <var
class="OPTION">-t</var> (show contents of the fixed tables) and <var
class="OPTION">-d</var> (disassemble <acronym class="ACRONYM">AML</acronym> to <acronym
class="ACRONYM">ASL</acronym>) options. See the <a
href="acpi-debug.html#ACPI-SUBMITDEBUG">Submitting Debugging Information</a> section for
an example syntax.</p>

<p>The simplest first check you can do is to recompile your <acronym
class="ACRONYM">ASL</acronym> to check for errors. Warnings can usually be ignored but
errors are bugs that will usually prevent <acronym class="ACRONYM">ACPI</acronym> from
working correctly. To recompile your <acronym class="ACRONYM">ASL</acronym>, issue the
following command:</p>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iasl your.asl</kbd>
</pre>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="ACPI-FIXASL" name="ACPI-FIXASL">11.16.5. Fixing Your <acronym
class="ACRONYM">ASL</acronym></a></h2>

<p>In the long run, our goal is for almost everyone to have <acronym
class="ACRONYM">ACPI</acronym> work without any user intervention. At this point,
however, we are still developing workarounds for common mistakes made by the <acronym
class="ACRONYM">BIOS</acronym> vendors. The Microsoft interpreter (<tt
class="FILENAME">acpi.sys</tt> and <tt class="FILENAME">acpiec.sys</tt>) does not
strictly check for adherence to the standard, and thus many <acronym
class="ACRONYM">BIOS</acronym> vendors who only test <acronym
class="ACRONYM">ACPI</acronym> under Windows never fix their <acronym
class="ACRONYM">ASL</acronym>. We hope to continue to identify and document exactly what
non-standard behavior is allowed by Microsoft's interpreter and replicate it so FreeBSD
can work without forcing users to fix the <acronym class="ACRONYM">ASL</acronym>. As a
workaround and to help us identify behavior, you can fix the <acronym
class="ACRONYM">ASL</acronym> manually. If this works for you, please send a <span
class="CITEREFENTRY"><span class="REFENTRYTITLE">diff</span>(1)</span> of the old and new
<acronym class="ACRONYM">ASL</acronym> so we can possibly work around the buggy behavior
in <acronym class="ACRONYM">ACPI-CA</acronym> and thus make your fix unnecessary.</p>

<p>Here is a list of common error messages, their cause, and how to fix them:</p>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN17134" name="AEN17134">11.16.5.1. _OS dependencies</a></h3>

<p>Some <acronym class="ACRONYM">AML</acronym> assumes the world consists of various
Windows versions. You can tell FreeBSD to claim it is any <acronym
class="ACRONYM">OS</acronym> to see if this fixes problems you may have. An easy way to
override this is to set <var class="OPTION">hw.acpi.osname</var>=``Windows 2001'' in <tt
class="FILENAME">/boot/loader.conf</tt> or other similar strings you find in the <acronym
class="ACRONYM">ASL</acronym>.</p>
</div>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN17143" name="AEN17143">11.16.5.2. Missing Return
statements</a></h3>

<p>Some methods do not explicitly return a value as the standard requires. While <acronym
class="ACRONYM">ACPI-CA</acronym> does not handle this, FreeBSD has a workaround that
allows it to return the value implicitly. You can also add explicit Return statements
where required if you know what value should be returned. To force <tt
class="COMMAND">iasl</tt> to compile the <acronym class="ACRONYM">ASL</acronym>, use the
<var class="OPTION">-f</var> flag.</p>
</div>

<div class="SECT3">
<h3 class="SECT3"><a id="AEN17150" name="AEN17150">11.16.5.3. Overriding the Default
<acronym class="ACRONYM">AML</acronym></a></h3>

<p>After you customize <tt class="FILENAME">your.asl</tt>, you will want to compile it,
run:</p>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iasl your.asl</kbd>
</pre>

<p>You can add the <var class="OPTION">-f</var> flag to force creation of the <acronym
class="ACRONYM">AML</acronym>, even if there are errors during compilation. Remember that
some errors (e.g., missing Return statements) are automatically worked around by the
interpreter.</p>

<p><tt class="FILENAME">DSDT.aml</tt> is the default output filename for <tt
class="COMMAND">iasl</tt>. You can load this instead of your <acronym
class="ACRONYM">BIOS</acronym>'s buggy copy (which is still present in flash memory) by
editing <tt class="FILENAME">/boot/loader.conf</tt> as follows:</p>

<pre class="PROGRAMLISTING">
acpi_dsdt_load="YES"
acpi_dsdt_name="/boot/DSDT.aml"
</pre>

<p>Be sure to copy your <tt class="FILENAME">DSDT.aml</tt> to the <tt
class="FILENAME">/boot</tt> directory.</p>
</div>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="ACPI-DEBUGOUTPUT" name="ACPI-DEBUGOUTPUT">11.16.6. Getting
Debugging Output From <acronym class="ACRONYM">ACPI</acronym></a></h2>

<p>The <acronym class="ACRONYM">ACPI</acronym> driver has a very flexible debugging
facility. It allows you to specify a set of subsystems as well as the level of verbosity.
The subsystems you wish to debug are specified as ``layers'' and are broken down into
<acronym class="ACRONYM">ACPI-CA</acronym> components (ACPI_ALL_COMPONENTS) and <acronym
class="ACRONYM">ACPI</acronym> hardware support (ACPI_ALL_DRIVERS). The verbosity of
debugging output is specified as the ``level'' and ranges from ACPI_LV_ERROR (just report
errors) to ACPI_LV_VERBOSE (everything). The ``level'' is a bitmask so multiple options
can be set at once, separated by spaces. In practice, you will want to use a serial
console to log the output if it is so long it flushes the console message buffer. A full
list of the individual layers and levels is found in the <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpi</span>(4)</span> manual page.</p>

<p>Debugging output is not enabled by default. To enable it, add <var
class="OPTION">options ACPI_DEBUG</var> to your kernel config if <acronym
class="ACRONYM">ACPI</acronym> is compiled into the kernel. You can add <var
class="OPTION">ACPI_DEBUG=1</var> to your <tt class="FILENAME">/etc/make.conf</tt> to
enable it globally. If it is a module, you can recompile just your <tt
class="FILENAME">acpi.ko</tt> module as follows:</p>

<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cd /sys/modules/acpi/acpi
&amp;&amp; make clean &amp;&amp;
make ACPI_DEBUG=1</kbd>
</pre>

<p>Install <tt class="FILENAME">acpi.ko</tt> in <tt class="FILENAME">/boot/kernel</tt>
and add your desired level and layer to <tt class="FILENAME">loader.conf</tt>. This
example enables debug messages for all <acronym class="ACRONYM">ACPI-CA</acronym>
components and all <acronym class="ACRONYM">ACPI</acronym> hardware drivers (<acronym
class="ACRONYM">CPU</acronym>, <acronym class="ACRONYM">LID</acronym>, etc.) It will only
output error messages, the least verbose level.</p>

<pre class="PROGRAMLISTING">
debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
debug.acpi.level="ACPI_LV_ERROR"
</pre>

<p>If the information you want is triggered by a specific event (say, a suspend and then
resume), you can leave out changes to <tt class="FILENAME">loader.conf</tt> and instead
use <tt class="COMMAND">sysctl</tt> to specify the layer and level after booting and
preparing your system for the specific event. The <tt class="COMMAND">sysctl</tt>s are
named the same as the tunables in <tt class="FILENAME">loader.conf</tt>.</p>
</div>

<div class="SECT2">
<h2 class="SECT2"><a id="ACPI-REFERENCES" name="ACPI-REFERENCES">11.16.7.
References</a></h2>

<p>More information about <acronym class="ACRONYM">ACPI</acronym> may be found in the
following locations:</p>

<ul>
<li>
<p>The <a href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-acpi"
target="_top">FreeBSD ACPI 邮件列表</a></p>
</li>

<li>
<p>The <acronym class="ACRONYM">ACPI</acronym> Mailing List Archives <a
href="http://lists.freebsd.org/pipermail/freebsd-acpi/"
target="_top">http://lists.freebsd.org/pipermail/freebsd-acpi/</a></p>
</li>

<li>
<p>The old <acronym class="ACRONYM">ACPI</acronym> Mailing List Archives <a
href="http://home.jp.FreeBSD.org/mail-list/acpi-jp/"
target="_top">http://home.jp.FreeBSD.org/mail-list/acpi-jp/</a></p>
</li>

<li>
<p>The <acronym class="ACRONYM">ACPI</acronym> 2.0 标准 <a
href="http://acpi.info/spec.htm" target="_top">http://acpi.info/spec.htm</a></p>
</li>

<li>
<p>FreeBSD 手册页: <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpi</span>(4)</span>, <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpi_thermal</span>(4)</span>, <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpidump</span>(8)</span>, <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">iasl</span>(8)</span>, <span class="CITEREFENTRY"><span
class="REFENTRYTITLE">acpidb</span>(8)</span></p>
</li>

<li>
<p><a href="http://www.cpqlinux.com/acpi-howto.html#fix_broken_dsdt"
target="_top"><acronym class="ACRONYM">DSDT</acronym> 调试资源</a>. (使用 Compaq
作为例子但通常情况下都很有用。)</p>
</li>
</ul>
</div>
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