[PATCH 29/63] dyndbg-doc: add classmap info to howto

[PATCH 29/63] dyndbg-doc: add classmap info to howto

[Jim Cromie]

Describe the 3 API macros providing dynamic_debug's classmaps

DYNDBG_CLASSMAP_DEFINE - create, exports a module's classmap
DYNDBG_CLASSMAP_USE    - refer to exported map
DYNDBG_CLASSMAP_PARAM  - bind control param to the classmap
DYNDBG_CLASSMAP_PARAM_REF + use module's storage - __drm_debug

cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5 adjustments per Randy Dunlap
v7 checkpatch fixes
v8 more
v9 rewords
---
 .../admin-guide/dynamic-debug-howto.rst       | 79 ++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 691e0f7d4de1..391e40a510c9 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -230,7 +230,6 @@ the ``p`` flag has meaning, other flags are ignored.
 Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
-
 Debug messages during Boot Process
 ==================================
 
@@ -380,3 +379,81 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
 in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+The "class" keyword selects prdbgs based on author supplied,
+domain-oriented names.  This complements the nested-scope keywords:
+module, file, function, line.
+
+The main difference from the others: class'd prdbgs must be named to
+be changed.  This protects them from generic overwrite:
+
+  # IOW this cannot undo any DRM.debug settings
+  :#> ddcmd -p
+
+So each class must be enabled individually (no wildcards):
+
+  :#> ddcmd class DRM_UT_CORE +p
+  :#> ddcmd class DRM_UT_KMS +p
+  # or more selectively
+  :#> ddcmd class DRM_UT_CORE module drm +p
+
+Or the legacy/normal (more convenient) way:
+
+  :#> echo 0x1ff > /sys/module/drm/parameters/debug
+
+Dynamic Debug Classmap API
+==========================
+
+DRM.debug is built upon:
+  ~23 macros, all passing a DRM_UT_* constant as arg-1.
+  ~5000 calls to them, across drivers/gpu/drm/*
+  bits in /sys/module/drm/parameters/debug control all DRM_UT_* together
+
+The const short ints are good for optimizing compilers; a classmaps
+design goal was to keep that.  So basically .classid === category.
+
+And since prdbgs are cataloged with just a DRM_UT_* to identify them,
+the "class" keyword maps known classnames to those reserved IDs, and
+by explicitly requiring "class FOO" in queries, we protect FOO class'd
+debugs from overwrite by generic queries.
+
+Its expected that other classmap users will also provide debug-macros
+using an enum-defined categorization scheme like DRM's, and dyndbg can
+be adapted under them similarly.
+
+DYNDBG_CLASSMAP_DEFINE(var,type,_base,classnames) - this maps
+classnames onto class-ids starting at _base, it also maps the
+names onto CLASSMAP_PARAM bits 0..N.
+
+DYNDBG_CLASSMAP_USE(var) - modules call this to refer to the var
+_DEFINEd elsewhere (and exported).
+
+Classmaps are opt-in: modules invoke _DEFINE or _USE to authorize
+dyndbg to update those classes.  "class FOO" queries are validated
+against the classes, this finds the classid to alter; classes are not
+directly selectable by their classid.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
+DEFINEd classmap, and associates it to the param's data-store.  This
+state is then applied to DEFINEr and USEr modules when they're modprobed.
+
+The PARAM interface also enforces the DD_CLASS_TYPE_LEVEL_NUM relation
+amongst the contained classnames; all classes are independent in the
+control parser itself; there is no implied meaning in names like "V4".
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones.  This won't be reflected in the PARAM readback value,
+but the class'd pr_debug callsites can be forced off by toggling the
+classmap-kparam all-on then all-off.
-- 
2.47.0

Re: [PATCH 29/63] dyndbg-doc: add classmap info to howto

[Bagas Sanjaya]

[-- Attachment #1: Type: text/plain, Size: 4199 bytes --]

On Thu, Oct 31, 2024 at 02:44:03AM -0600, Jim Cromie wrote:
> +The main difference from the others: class'd prdbgs must be named to
> +be changed.  This protects them from generic overwrite:
> +
> +  # IOW this cannot undo any DRM.debug settings
> +  :#> ddcmd -p
> +
> +So each class must be enabled individually (no wildcards):
> +
> +  :#> ddcmd class DRM_UT_CORE +p
> +  :#> ddcmd class DRM_UT_KMS +p
> +  # or more selectively
> +  :#> ddcmd class DRM_UT_CORE module drm +p
> +
> +Or the legacy/normal (more convenient) way:
> +
> +  :#> echo 0x1ff > /sys/module/drm/parameters/debug

Format command sequences as literal code blocks (like in the rest of docs):

---- >8 ----
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 3068d134fcc6d9..a826b972461fe5 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -388,19 +388,19 @@ domain-oriented names.  This complements the nested-scope keywords:
 module, file, function, line.
 
 The main difference from the others: class'd prdbgs must be named to
-be changed.  This protects them from generic overwrite:
+be changed.  This protects them from generic overwrite::
 
   # IOW this cannot undo any DRM.debug settings
   :#> ddcmd -p
 
-So each class must be enabled individually (no wildcards):
+So each class must be enabled individually (no wildcards)::
 
   :#> ddcmd class DRM_UT_CORE +p
   :#> ddcmd class DRM_UT_KMS +p
   # or more selectively
   :#> ddcmd class DRM_UT_CORE module drm +p
 
-Or the legacy/normal (more convenient) way:
+Or the legacy/normal (more convenient) way::
 
   :#> echo 0x1ff > /sys/module/drm/parameters/debug
 
> +DYNDBG_CLASSMAP_DEFINE(var,type,_base,classnames) - this maps
> +classnames onto class-ids starting at _base, it also maps the
> +names onto CLASSMAP_PARAM bits 0..N.
> +
> +DYNDBG_CLASSMAP_USE(var) - modules call this to refer to the var
> +_DEFINEd elsewhere (and exported).

Shouldn't these DYNDBG_CLASSMAP_* descriptions be list?

> +
> +Classmaps are opt-in: modules invoke _DEFINE or _USE to authorize
> +dyndbg to update those classes.  "class FOO" queries are validated
> +against the classes, this finds the classid to alter; classes are not
> +directly selectable by their classid.
> +
> +There are 2 types of classmaps:
> +
> + DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
> + DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)

For lists, format them as such otherwise these will be outputted as long
paragraphs:

---- >8 ----
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index a826b972461fe5..c70e34f01822a2 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -408,9 +408,10 @@ Dynamic Debug Classmap API
 ==========================
 
 DRM.debug is built upon:
-  ~23 macros, all passing a DRM_UT_* constant as arg-1.
-  ~5000 calls to them, across drivers/gpu/drm/*
-  bits in /sys/module/drm/parameters/debug control all DRM_UT_* together
+
+- 23 macros, all passing a DRM_UT_* constant as arg-1.
+- 5000 calls to them, across ``drivers/gpu/drm/*`` bits in
+  ``/sys/module/drm/parameters/debug`` control all DRM_UT_* together
 
 The const short ints are good for optimizing compilers; a classmaps
 design goal was to keep that.  So basically .classid === category.
@@ -438,8 +439,8 @@ directly selectable by their classid.
 
 There are 2 types of classmaps:
 
- DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
- DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+- ``DD_CLASS_TYPE_DISJOINT_BITS``: classes are independent, like DRM.debug
+- ``DD_CLASS_TYPE_LEVEL_NUM``: classes are relative, ordered (V3 > V2)
 
 DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
 DEFINEd classmap, and associates it to the param's data-store.  This

Thanks.

-- 
An old man doll... just what I always wanted! - Clara

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[PATCH 29/63] dyndbg-doc: add classmap info to howto

[Jim Cromie]

Describe the 3 API macros providing dynamic_debug's classmaps

DYNDBG_CLASSMAP_DEFINE - create, exports a module's classmap
DYNDBG_CLASSMAP_USE    - refer to exported map
DYNDBG_CLASSMAP_PARAM  - bind control param to the classmap
DYNDBG_CLASSMAP_PARAM_REF + use module's storage - __drm_debug

cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5 adjustments per Randy Dunlap
v7 checkpatch fixes
v8 more
v9 rewords
---
 .../admin-guide/dynamic-debug-howto.rst       | 79 ++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 691e0f7d4de1..391e40a510c9 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -230,7 +230,6 @@ the ``p`` flag has meaning, other flags are ignored.
 Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
-
 Debug messages during Boot Process
 ==================================
 
@@ -380,3 +379,81 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
 in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+The "class" keyword selects prdbgs based on author supplied,
+domain-oriented names.  This complements the nested-scope keywords:
+module, file, function, line.
+
+The main difference from the others: class'd prdbgs must be named to
+be changed.  This protects them from generic overwrite:
+
+  # IOW this cannot undo any DRM.debug settings
+  :#> ddcmd -p
+
+So each class must be enabled individually (no wildcards):
+
+  :#> ddcmd class DRM_UT_CORE +p
+  :#> ddcmd class DRM_UT_KMS +p
+  # or more selectively
+  :#> ddcmd class DRM_UT_CORE module drm +p
+
+Or the legacy/normal (more convenient) way:
+
+  :#> echo 0x1ff > /sys/module/drm/parameters/debug
+
+Dynamic Debug Classmap API
+==========================
+
+DRM.debug is built upon:
+  ~23 macros, all passing a DRM_UT_* constant as arg-1.
+  ~5000 calls to them, across drivers/gpu/drm/*
+  bits in /sys/module/drm/parameters/debug control all DRM_UT_* together
+
+The const short ints are good for optimizing compilers; a classmaps
+design goal was to keep that.  So basically .classid === category.
+
+And since prdbgs are cataloged with just a DRM_UT_* to identify them,
+the "class" keyword maps known classnames to those reserved IDs, and
+by explicitly requiring "class FOO" in queries, we protect FOO class'd
+debugs from overwrite by generic queries.
+
+Its expected that other classmap users will also provide debug-macros
+using an enum-defined categorization scheme like DRM's, and dyndbg can
+be adapted under them similarly.
+
+DYNDBG_CLASSMAP_DEFINE(var,type,_base,classnames) - this maps
+classnames onto class-ids starting at _base, it also maps the
+names onto CLASSMAP_PARAM bits 0..N.
+
+DYNDBG_CLASSMAP_USE(var) - modules call this to refer to the var
+_DEFINEd elsewhere (and exported).
+
+Classmaps are opt-in: modules invoke _DEFINE or _USE to authorize
+dyndbg to update those classes.  "class FOO" queries are validated
+against the classes, this finds the classid to alter; classes are not
+directly selectable by their classid.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
+DEFINEd classmap, and associates it to the param's data-store.  This
+state is then applied to DEFINEr and USEr modules when they're modprobed.
+
+The PARAM interface also enforces the DD_CLASS_TYPE_LEVEL_NUM relation
+amongst the contained classnames; all classes are independent in the
+control parser itself; there is no implied meaning in names like "V4".
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones.  This won't be reflected in the PARAM readback value,
+but the class'd pr_debug callsites can be forced off by toggling the
+classmap-kparam all-on then all-off.
-- 
2.47.0

[PATCH 29/63] dyndbg-doc: add classmap info to howto

[Jim Cromie]

Describe the 3 API macros providing dynamic_debug's classmaps

DYNDBG_CLASSMAP_DEFINE - create, exports a module's classmap
DYNDBG_CLASSMAP_USE    - refer to exported map
DYNDBG_CLASSMAP_PARAM  - bind control param to the classmap
DYNDBG_CLASSMAP_PARAM_REF + use module's storage - __drm_debug

cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5 adjustments per Randy Dunlap
v7 checkpatch fixes
v8 more
v9 rewords
---
 .../admin-guide/dynamic-debug-howto.rst       | 79 ++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 691e0f7d4de1..391e40a510c9 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -230,7 +230,6 @@ the ``p`` flag has meaning, other flags are ignored.
 Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
-
 Debug messages during Boot Process
 ==================================
 
@@ -380,3 +379,81 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
 in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+The "class" keyword selects prdbgs based on author supplied,
+domain-oriented names.  This complements the nested-scope keywords:
+module, file, function, line.
+
+The main difference from the others: class'd prdbgs must be named to
+be changed.  This protects them from generic overwrite:
+
+  # IOW this cannot undo any DRM.debug settings
+  :#> ddcmd -p
+
+So each class must be enabled individually (no wildcards):
+
+  :#> ddcmd class DRM_UT_CORE +p
+  :#> ddcmd class DRM_UT_KMS +p
+  # or more selectively
+  :#> ddcmd class DRM_UT_CORE module drm +p
+
+Or the legacy/normal (more convenient) way:
+
+  :#> echo 0x1ff > /sys/module/drm/parameters/debug
+
+Dynamic Debug Classmap API
+==========================
+
+DRM.debug is built upon:
+  ~23 macros, all passing a DRM_UT_* constant as arg-1.
+  ~5000 calls to them, across drivers/gpu/drm/*
+  bits in /sys/module/drm/parameters/debug control all DRM_UT_* together
+
+The const short ints are good for optimizing compilers; a classmaps
+design goal was to keep that.  So basically .classid === category.
+
+And since prdbgs are cataloged with just a DRM_UT_* to identify them,
+the "class" keyword maps known classnames to those reserved IDs, and
+by explicitly requiring "class FOO" in queries, we protect FOO class'd
+debugs from overwrite by generic queries.
+
+Its expected that other classmap users will also provide debug-macros
+using an enum-defined categorization scheme like DRM's, and dyndbg can
+be adapted under them similarly.
+
+DYNDBG_CLASSMAP_DEFINE(var,type,_base,classnames) - this maps
+classnames onto class-ids starting at _base, it also maps the
+names onto CLASSMAP_PARAM bits 0..N.
+
+DYNDBG_CLASSMAP_USE(var) - modules call this to refer to the var
+_DEFINEd elsewhere (and exported).
+
+Classmaps are opt-in: modules invoke _DEFINE or _USE to authorize
+dyndbg to update those classes.  "class FOO" queries are validated
+against the classes, this finds the classid to alter; classes are not
+directly selectable by their classid.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
+DEFINEd classmap, and associates it to the param's data-store.  This
+state is then applied to DEFINEr and USEr modules when they're modprobed.
+
+The PARAM interface also enforces the DD_CLASS_TYPE_LEVEL_NUM relation
+amongst the contained classnames; all classes are independent in the
+control parser itself; there is no implied meaning in names like "V4".
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones.  This won't be reflected in the PARAM readback value,
+but the class'd pr_debug callsites can be forced off by toggling the
+classmap-kparam all-on then all-off.
-- 
2.47.0

[PATCH 29/63] dyndbg-doc: add classmap info to howto

[Jim Cromie]

Describe the 3 API macros providing dynamic_debug's classmaps

DYNDBG_CLASSMAP_DEFINE - create, exports a module's classmap
DYNDBG_CLASSMAP_USE    - refer to exported map
DYNDBG_CLASSMAP_PARAM  - bind control param to the classmap
DYNDBG_CLASSMAP_PARAM_REF + use module's storage - __drm_debug

cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5 adjustments per Randy Dunlap
v7 checkpatch fixes
v8 more
v9 rewords
---
 .../admin-guide/dynamic-debug-howto.rst       | 79 ++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 691e0f7d4de1..391e40a510c9 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -230,7 +230,6 @@ the ``p`` flag has meaning, other flags are ignored.
 Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
 To clear all flags at once, use ``=_`` or ``-fslmpt``.
 
-
 Debug messages during Boot Process
 ==================================
 
@@ -380,3 +379,81 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
 For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
 its ``prefix_str`` argument, if it is constant string; or ``hexdump``
 in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+The "class" keyword selects prdbgs based on author supplied,
+domain-oriented names.  This complements the nested-scope keywords:
+module, file, function, line.
+
+The main difference from the others: class'd prdbgs must be named to
+be changed.  This protects them from generic overwrite:
+
+  # IOW this cannot undo any DRM.debug settings
+  :#> ddcmd -p
+
+So each class must be enabled individually (no wildcards):
+
+  :#> ddcmd class DRM_UT_CORE +p
+  :#> ddcmd class DRM_UT_KMS +p
+  # or more selectively
+  :#> ddcmd class DRM_UT_CORE module drm +p
+
+Or the legacy/normal (more convenient) way:
+
+  :#> echo 0x1ff > /sys/module/drm/parameters/debug
+
+Dynamic Debug Classmap API
+==========================
+
+DRM.debug is built upon:
+  ~23 macros, all passing a DRM_UT_* constant as arg-1.
+  ~5000 calls to them, across drivers/gpu/drm/*
+  bits in /sys/module/drm/parameters/debug control all DRM_UT_* together
+
+The const short ints are good for optimizing compilers; a classmaps
+design goal was to keep that.  So basically .classid === category.
+
+And since prdbgs are cataloged with just a DRM_UT_* to identify them,
+the "class" keyword maps known classnames to those reserved IDs, and
+by explicitly requiring "class FOO" in queries, we protect FOO class'd
+debugs from overwrite by generic queries.
+
+Its expected that other classmap users will also provide debug-macros
+using an enum-defined categorization scheme like DRM's, and dyndbg can
+be adapted under them similarly.
+
+DYNDBG_CLASSMAP_DEFINE(var,type,_base,classnames) - this maps
+classnames onto class-ids starting at _base, it also maps the
+names onto CLASSMAP_PARAM bits 0..N.
+
+DYNDBG_CLASSMAP_USE(var) - modules call this to refer to the var
+_DEFINEd elsewhere (and exported).
+
+Classmaps are opt-in: modules invoke _DEFINE or _USE to authorize
+dyndbg to update those classes.  "class FOO" queries are validated
+against the classes, this finds the classid to alter; classes are not
+directly selectable by their classid.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
+DEFINEd classmap, and associates it to the param's data-store.  This
+state is then applied to DEFINEr and USEr modules when they're modprobed.
+
+The PARAM interface also enforces the DD_CLASS_TYPE_LEVEL_NUM relation
+amongst the contained classnames; all classes are independent in the
+control parser itself; there is no implied meaning in names like "V4".
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones.  This won't be reflected in the PARAM readback value,
+but the class'd pr_debug callsites can be forced off by toggling the
+classmap-kparam all-on then all-off.
-- 
2.48.1