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Date:   Thu, 25 Apr 2019 00:55:01 +0800
From:   Changbin Du <changbin.du@gmail.com>
To:     Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc:     Changbin Du <changbin.du@gmail.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Bjorn Helgaas <bhelgaas@google.com>, rjw@rjwysocki.net,
        linux-pci@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com,
        x86@kernel.org, fenghua.yu@intel.com,
        linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org,
        linux-gpio@vger.kernel.org
Subject: Re: [PATCH v4 17/63] Documentation: ACPI: move method-tracing.txt to
 firmware-guide/acpi and convert to rsST
Message-ID: <20190424165459.npdedjxrdart7wyk@mail.google.com>
References: <20190423162932.21428-1-changbin.du@gmail.com>
 <20190423162932.21428-18-changbin.du@gmail.com>
 <20190424112638.1b9f7cfb@coco.lan>
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On Wed, Apr 24, 2019 at 11:26:38AM -0300, Mauro Carvalho Chehab wrote:
> Em Wed, 24 Apr 2019 00:28:46 +0800
> Changbin Du <changbin.du@gmail.com> escreveu:
> 
> > This converts the plain text documentation to reStructuredText format and
> > add it to Sphinx TOC tree. No essential content change.
> > 
> > Signed-off-by: Changbin Du <changbin.du@gmail.com>
> > ---
> >  Documentation/acpi/method-tracing.txt         | 192 ---------------
> >  Documentation/firmware-guide/acpi/index.rst   |   1 +
> >  .../firmware-guide/acpi/method-tracing.rst    | 225 ++++++++++++++++++
> >  3 files changed, 226 insertions(+), 192 deletions(-)
> >  delete mode 100644 Documentation/acpi/method-tracing.txt
> >  create mode 100644 Documentation/firmware-guide/acpi/method-tracing.rst
> > 
> > diff --git a/Documentation/acpi/method-tracing.txt b/Documentation/acpi/method-tracing.txt
> > deleted file mode 100644
> > index 0aba14c8f459..000000000000
> > --- a/Documentation/acpi/method-tracing.txt
> > +++ /dev/null
> > @@ -1,192 +0,0 @@
> > -ACPICA Trace Facility
> > -
> > -Copyright (C) 2015, Intel Corporation
> > -Author: Lv Zheng <lv.zheng@intel.com>
> > -
> > -
> > -Abstract:
> > -
> > -This document describes the functions and the interfaces of the method
> > -tracing facility.
> > -
> > -1. Functionalities and usage examples:
> > -
> > -   ACPICA provides method tracing capability. And two functions are
> > -   currently implemented using this capability.
> > -
> > -   A. Log reducer
> > -   ACPICA subsystem provides debugging outputs when CONFIG_ACPI_DEBUG is
> > -   enabled. The debugging messages which are deployed via
> > -   ACPI_DEBUG_PRINT() macro can be reduced at 2 levels - per-component
> > -   level (known as debug layer, configured via
> > -   /sys/module/acpi/parameters/debug_layer) and per-type level (known as
> > -   debug level, configured via /sys/module/acpi/parameters/debug_level).
> > -
> > -   But when the particular layer/level is applied to the control method
> > -   evaluations, the quantity of the debugging outputs may still be too
> > -   large to be put into the kernel log buffer. The idea thus is worked out
> > -   to only enable the particular debug layer/level (normally more detailed)
> > -   logs when the control method evaluation is started, and disable the
> > -   detailed logging when the control method evaluation is stopped.
> > -
> > -   The following command examples illustrate the usage of the "log reducer"
> > -   functionality:
> > -   a. Filter out the debug layer/level matched logs when control methods
> > -      are being evaluated:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0xXXXXXXXX" > trace_debug_layer
> > -      # echo "0xYYYYYYYY" > trace_debug_level
> > -      # echo "enable" > trace_state
> > -   b. Filter out the debug layer/level matched logs when the specified
> > -      control method is being evaluated:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0xXXXXXXXX" > trace_debug_layer
> > -      # echo "0xYYYYYYYY" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "method" > /sys/module/acpi/parameters/trace_state
> > -   c. Filter out the debug layer/level matched logs when the specified
> > -      control method is being evaluated for the first time:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0xXXXXXXXX" > trace_debug_layer
> > -      # echo "0xYYYYYYYY" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "method-once" > /sys/module/acpi/parameters/trace_state
> > -   Where:
> > -      0xXXXXXXXX/0xYYYYYYYY: Refer to Documentation/acpi/debug.txt for
> > -			     possible debug layer/level masking values.
> > -      \PPPP.AAAA.TTTT.HHHH: Full path of a control method that can be found
> > -			    in the ACPI namespace. It needn't be an entry
> > -			    of a control method evaluation.
> > -
> > -   B. AML tracer
> > -
> > -   There are special log entries added by the method tracing facility at
> > -   the "trace points" the AML interpreter starts/stops to execute a control
> > -   method, or an AML opcode. Note that the format of the log entries are
> > -   subject to change:
> > -     [    0.186427]   exdebug-0398 ex_trace_point        : Method Begin [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
> > -     [    0.186630]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905c88:If] execution.
> > -     [    0.186820]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905cc0:LEqual] execution.
> > -     [    0.187010]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905a20:-NamePath-] execution.
> > -     [    0.187214]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905a20:-NamePath-] execution.
> > -     [    0.187407]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905f60:One] execution.
> > -     [    0.187594]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905f60:One] execution.
> > -     [    0.187789]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905cc0:LEqual] execution.
> > -     [    0.187980]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905cc0:Return] execution.
> > -     [    0.188146]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905f60:One] execution.
> > -     [    0.188334]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905f60:One] execution.
> > -     [    0.188524]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905cc0:Return] execution.
> > -     [    0.188712]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905c88:If] execution.
> > -     [    0.188903]   exdebug-0398 ex_trace_point        : Method End [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
> > -
> > -   Developers can utilize these special log entries to track the AML
> > -   interpretion, thus can aid issue debugging and performance tuning. Note
> > -   that, as the "AML tracer" logs are implemented via ACPI_DEBUG_PRINT()
> > -   macro, CONFIG_ACPI_DEBUG is also required to be enabled for enabling
> > -   "AML tracer" logs.
> > -
> > -   The following command examples illustrate the usage of the "AML tracer"
> > -   functionality:
> > -   a. Filter out the method start/stop "AML tracer" logs when control
> > -      methods are being evaluated:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0x80" > trace_debug_layer
> > -      # echo "0x10" > trace_debug_level
> > -      # echo "enable" > trace_state
> > -   b. Filter out the method start/stop "AML tracer" when the specified
> > -      control method is being evaluated:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0x80" > trace_debug_layer
> > -      # echo "0x10" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "method" > trace_state
> > -   c. Filter out the method start/stop "AML tracer" logs when the specified
> > -      control method is being evaluated for the first time:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0x80" > trace_debug_layer
> > -      # echo "0x10" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "method-once" > trace_state
> > -   d. Filter out the method/opcode start/stop "AML tracer" when the
> > -      specified control method is being evaluated:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0x80" > trace_debug_layer
> > -      # echo "0x10" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "opcode" > trace_state
> > -   e. Filter out the method/opcode start/stop "AML tracer" when the
> > -      specified control method is being evaluated for the first time:
> > -      # cd /sys/module/acpi/parameters
> > -      # echo "0x80" > trace_debug_layer
> > -      # echo "0x10" > trace_debug_level
> > -      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > -      # echo "opcode-opcode" > trace_state
> > -
> > -  Note that all above method tracing facility related module parameters can
> > -  be used as the boot parameters, for example:
> > -      acpi.trace_debug_layer=0x80 acpi.trace_debug_level=0x10 \
> > -      acpi.trace_method_name=\_SB.LID0._LID acpi.trace_state=opcode-once
> > -
> > -2. Interface descriptions:
> > -
> > -   All method tracing functions can be configured via ACPI module
> > -   parameters that are accessible at /sys/module/acpi/parameters/:
> > -
> > -   trace_method_name
> > -	The full path of the AML method that the user wants to trace.
> > -	Note that the full path shouldn't contain the trailing "_"s in its
> > -	name segments but may contain "\" to form an absolute path.
> > -
> > -   trace_debug_layer
> > -	The temporary debug_layer used when the tracing feature is enabled.
> > -	Using ACPI_EXECUTER (0x80) by default, which is the debug_layer
> > -	used to match all "AML tracer" logs.
> > -
> > -   trace_debug_level
> > -	The temporary debug_level used when the tracing feature is enabled.
> > -	Using ACPI_LV_TRACE_POINT (0x10) by default, which is the
> > -	debug_level used to match all "AML tracer" logs.
> > -
> > -   trace_state
> > -	The status of the tracing feature.
> > -	Users can enable/disable this debug tracing feature by executing
> > -	the following command:
> > -	    # echo string > /sys/module/acpi/parameters/trace_state
> > -	Where "string" should be one of the following:
> > -	"disable"
> > -	    Disable the method tracing feature.
> > -	"enable"
> > -	    Enable the method tracing feature.
> > -	    ACPICA debugging messages matching
> > -	    "trace_debug_layer/trace_debug_level" during any method
> > -	    execution will be logged.
> > -	"method"
> > -	    Enable the method tracing feature.
> > -	    ACPICA debugging messages matching
> > -	    "trace_debug_layer/trace_debug_level" during method execution
> > -	    of "trace_method_name" will be logged.
> > -	"method-once"
> > -	    Enable the method tracing feature.
> > -	    ACPICA debugging messages matching
> > -	    "trace_debug_layer/trace_debug_level" during method execution
> > -	    of "trace_method_name" will be logged only once.
> > -	"opcode"
> > -	    Enable the method tracing feature.
> > -	    ACPICA debugging messages matching
> > -	    "trace_debug_layer/trace_debug_level" during method/opcode
> > -	    execution of "trace_method_name" will be logged.
> > -	"opcode-once"
> > -	    Enable the method tracing feature.
> > -	    ACPICA debugging messages matching
> > -	    "trace_debug_layer/trace_debug_level" during method/opcode
> > -	    execution of "trace_method_name" will be logged only once.
> > -	Note that, the difference between the "enable" and other feature
> > -        enabling options are:
> > -	1. When "enable" is specified, since
> > -	   "trace_debug_layer/trace_debug_level" shall apply to all control
> > -	   method evaluations, after configuring "trace_state" to "enable",
> > -	   "trace_method_name" will be reset to NULL.
> > -	2. When "method/opcode" is specified, if
> > -	   "trace_method_name" is NULL when "trace_state" is configured to
> > -	   these options, the "trace_debug_layer/trace_debug_level" will
> > -	   apply to all control method evaluations.
> > diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst
> > index a45fea11f998..287a7cbd82ac 100644
> > --- a/Documentation/firmware-guide/acpi/index.rst
> > +++ b/Documentation/firmware-guide/acpi/index.rst
> > @@ -13,6 +13,7 @@ ACPI Support
> >     enumeration
> >     osi
> >     method-customizing
> > +   method-tracing
> >     DSD-properties-rules
> >     debug
> >     gpio-properties
> > diff --git a/Documentation/firmware-guide/acpi/method-tracing.rst b/Documentation/firmware-guide/acpi/method-tracing.rst
> > new file mode 100644
> > index 000000000000..7a997ba168d7
> > --- /dev/null
> > +++ b/Documentation/firmware-guide/acpi/method-tracing.rst
> > @@ -0,0 +1,225 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +.. include:: <isonum.txt>
> > +
> > +=====================
> > +ACPICA Trace Facility
> > +=====================
> > +
> > +:Copyright: |copy| 2015, Intel Corporation
> > +:Author: Lv Zheng <lv.zheng@intel.com>
> > +
> > +
> > +:Abstract: This document describes the functions and the interfaces of the
> > +  method tracing facility.
> 
> Same comment as on other patches.
>
Fixed, thanks.

> > +
> > +1. Functionalities and usage examples
> > +=====================================
> > +
> > +ACPICA provides method tracing capability. And two functions are
> > +currently implemented using this capability.
> > +
> > +Log reducer
> > +--------------
> > +
> > +ACPICA subsystem provides debugging outputs when CONFIG_ACPI_DEBUG is
> > +enabled. The debugging messages which are deployed via
> > +ACPI_DEBUG_PRINT() macro can be reduced at 2 levels - per-component
> > +level (known as debug layer, configured via
> > +/sys/module/acpi/parameters/debug_layer) and per-type level (known as
> > +debug level, configured via /sys/module/acpi/parameters/debug_level).
> > +
> > +But when the particular layer/level is applied to the control method
> > +evaluations, the quantity of the debugging outputs may still be too
> > +large to be put into the kernel log buffer. The idea thus is worked out
> > +to only enable the particular debug layer/level (normally more detailed)
> > +logs when the control method evaluation is started, and disable the
> > +detailed logging when the control method evaluation is stopped.
> > +
> > +The following command examples illustrate the usage of the "log reducer"
> > +functionality:
> > +
> > +a. Filter out the debug layer/level matched logs when control methods
> > +   are being evaluated::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0xXXXXXXXX" > trace_debug_layer
> > +      # echo "0xYYYYYYYY" > trace_debug_level
> > +      # echo "enable" > trace_state
> > +
> > +b. Filter out the debug layer/level matched logs when the specified
> > +   control method is being evaluated::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0xXXXXXXXX" > trace_debug_layer
> > +      # echo "0xYYYYYYYY" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "method" > /sys/module/acpi/parameters/trace_state
> > +
> > +c. Filter out the debug layer/level matched logs when the specified
> > +   control method is being evaluated for the first time::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0xXXXXXXXX" > trace_debug_layer
> > +      # echo "0xYYYYYYYY" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "method-once" > /sys/module/acpi/parameters/trace_state
> > +
> > +Where:
> > +   0xXXXXXXXX/0xYYYYYYYY
> > +     Refer to Documentation/acpi/debug.txt for possible debug layer/level
> > +     masking values.
> > +   \PPPP.AAAA.TTTT.HHHH
> > +     Full path of a control method that can be found in the ACPI namespace.
> > +     It needn't be an entry of a control method evaluation.
> > +
> > +AML tracer
> > +-------------
> 
> The markup is bigger than the line. You should have seen a Sphinx
> warning here.
> 
> > +
> > +There are special log entries added by the method tracing facility at
> > +the "trace points" the AML interpreter starts/stops to execute a control
> > +method, or an AML opcode. Note that the format of the log entries are
> > +subject to change::
> > +
> > +   [    0.186427]   exdebug-0398 ex_trace_point        : Method Begin [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
> > +   [    0.186630]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905c88:If] execution.
> > +   [    0.186820]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905cc0:LEqual] execution.
> > +   [    0.187010]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905a20:-NamePath-] execution.
> > +   [    0.187214]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905a20:-NamePath-] execution.
> > +   [    0.187407]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905f60:One] execution.
> > +   [    0.187594]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905f60:One] execution.
> > +   [    0.187789]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905cc0:LEqual] execution.
> > +   [    0.187980]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905cc0:Return] execution.
> > +   [    0.188146]   exdebug-0398 ex_trace_point        : Opcode Begin [0xf5905f60:One] execution.
> > +   [    0.188334]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905f60:One] execution.
> > +   [    0.188524]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905cc0:Return] execution.
> > +   [    0.188712]   exdebug-0398 ex_trace_point        : Opcode End [0xf5905c88:If] execution.
> > +   [    0.188903]   exdebug-0398 ex_trace_point        : Method End [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
> > +
> > +Developers can utilize these special log entries to track the AML
> > +interpretion, thus can aid issue debugging and performance tuning. Note
> > +that, as the "AML tracer" logs are implemented via ACPI_DEBUG_PRINT()
> > +macro, CONFIG_ACPI_DEBUG is also required to be enabled for enabling
> > +"AML tracer" logs.
> > +
> > +The following command examples illustrate the usage of the "AML tracer"
> > +functionality:
> > +
> > +a. Filter out the method start/stop "AML tracer" logs when control
> > +   methods are being evaluated::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0x80" > trace_debug_layer
> > +      # echo "0x10" > trace_debug_level
> > +      # echo "enable" > trace_state
> > +
> > +b. Filter out the method start/stop "AML tracer" when the specified
> > +   control method is being evaluated::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0x80" > trace_debug_layer
> > +      # echo "0x10" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "method" > trace_state
> > +
> > +c. Filter out the method start/stop "AML tracer" logs when the specified
> > +   control method is being evaluated for the first time::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0x80" > trace_debug_layer
> > +      # echo "0x10" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "method-once" > trace_state
> > +
> > +d. Filter out the method/opcode start/stop "AML tracer" when the
> > +   specified control method is being evaluated::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0x80" > trace_debug_layer
> > +      # echo "0x10" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "opcode" > trace_state
> > +
> > +e. Filter out the method/opcode start/stop "AML tracer" when the
> > +   specified control method is being evaluated for the first time::
> > +
> > +      # cd /sys/module/acpi/parameters
> > +      # echo "0x80" > trace_debug_layer
> > +      # echo "0x10" > trace_debug_level
> > +      # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
> > +      # echo "opcode-opcode" > trace_state
> > +
> > +Note that all above method tracing facility related module parameters can
> > +be used as the boot parameters, for example::
> > +
> > +   acpi.trace_debug_layer=0x80 acpi.trace_debug_level=0x10 \
> > +   acpi.trace_method_name=\_SB.LID0._LID acpi.trace_state=opcode-once
> > +
> > +2. Interface descriptions
> > +=========================
> > +
> > +All method tracing functions can be configured via ACPI module
> > +parameters that are accessible at /sys/module/acpi/parameters/:
> > +
> > +trace_method_name
> > +The full path of the AML method that the user wants to trace.
> > +Note that the full path shouldn't contain the trailing "_"s in its
> > +name segments but may contain "\" to form an absolute path.
> > +
> 
> 
> > +trace_debug_layer
> > +The temporary debug_layer used when the tracing feature is enabled.
> > +Using ACPI_EXECUTER (0x80) by default, which is the debug_layer
> > +used to match all "AML tracer" logs.
> > +
> > +trace_debug_level
> > +The temporary debug_level used when the tracing feature is enabled.
> > +Using ACPI_LV_TRACE_POINT (0x10) by default, which is the
> > +debug_level used to match all "AML tracer" logs.
> > +
> > +trace_state
> > +The status of the tracing feature.
> > +Users can enable/disable this debug tracing feature by executing
> > +the following command::
> 
> For the above, please indent, in order to properly change the
> sysfs node font to bold. Also, mark paragraphs with a \n, e. g:
> 
>    trace_method_name
> 	The full path of the AML method that the user wants to trace.
> 
> 	Note that the full path shouldn't contain the trailing "_"s in its
> 	name segments but may contain "\" to form an absolute path.
> 
>    trace_debug_layer
> 	The temporary debug_layer used when the tracing feature is enabled.
> 
> 	Using ACPI_EXECUTER (0x80) by default, which is the debug_layer
> 	used to match all "AML tracer" logs.
> 
>    trace_debug_level
> 	The temporary debug_level used when the tracing feature is enabled.
> 
> 	Using ACPI_LV_TRACE_POINT (0x10) by default, which is the
> 	debug_level used to match all "AML tracer" logs.
> 
>    trace_state
> 	The status of the tracing feature.
> 
> 	Users can enable/disable this debug tracing feature by executing
> 	the following command::
> 
Done, thanks.

> After doing such changes:
> 
> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> 
> 
> > +
> > +   # echo string > /sys/module/acpi/parameters/trace_state
> > +
> > +Where "string" should be one of the following:
> > +
> > +"disable"
> > +      Disable the method tracing feature.
> > +"enable"
> > +      Enable the method tracing feature.
> > +      ACPICA debugging messages matching
> > +      "trace_debug_layer/trace_debug_level" during any method
> > +      execution will be logged.
> > +"method"
> > +      Enable the method tracing feature.
> > +      ACPICA debugging messages matching
> > +      "trace_debug_layer/trace_debug_level" during method execution
> > +      of "trace_method_name" will be logged.
> > +"method-once"
> > +      Enable the method tracing feature.
> > +      ACPICA debugging messages matching
> > +      "trace_debug_layer/trace_debug_level" during method execution
> > +      of "trace_method_name" will be logged only once.
> > +"opcode"
> > +      Enable the method tracing feature.
> > +      ACPICA debugging messages matching
> > +      "trace_debug_layer/trace_debug_level" during method/opcode
> > +      execution of "trace_method_name" will be logged.
> > +"opcode-once"
> > +      Enable the method tracing feature.
> > +      ACPICA debugging messages matching
> > +      "trace_debug_layer/trace_debug_level" during method/opcode
> > +      execution of "trace_method_name" will be logged only once.
> > +
> > +Note that, the difference between the "enable" and other feature
> > +enabling options are:
> > +
> > +1. When "enable" is specified, since
> > +   "trace_debug_layer/trace_debug_level" shall apply to all control
> > +   method evaluations, after configuring "trace_state" to "enable",
> > +   "trace_method_name" will be reset to NULL.
> > +2. When "method/opcode" is specified, if
> > +   "trace_method_name" is NULL when "trace_state" is configured to
> > +   these options, the "trace_debug_layer/trace_debug_level" will
> > +   apply to all control method evaluations.
> 
> 
> 
> Thanks,
> Mauro

-- 
Cheers,
Changbin Du