linux-kernel - [PATCH v8 12/16] amdgpu: use DEFINE_DYNAMIC_DEBUG

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Message-Id: <20210915163957.2949166-13-jim.cromie@gmail.com>
Date:   Wed, 15 Sep 2021 10:39:53 -0600
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, gregkh@...uxfoundation.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        amd-gfx@...ts.freedesktop.org, intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, daniel@...ll.ch
Cc:     Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v8 12/16] amdgpu: use DEFINE_DYNAMIC_DEBUG_CATEGORIES on existing prdbgs

logger_types.h defines many DC_LOG_*() categorized debug wrappers.
Most of these already use DRM debug API, so are controllable using
drm.debug, but others use a bare pr_debug("$prefix: .."), with 1 of 13
different class-prefixes matching ~/^\[[_A-Z]+\]:/

Use DEFINE_DYNAMIC_DEBUG_CATEGORIES to create a sysfs location which
maps from bits to these 13 sets of categorized pr_debugs to en/disable.

Makefile adds -DDYNAMIC_DEBUG_MODULE for CONFIG_DYNAMIC_DEBUG_CORE,
otherwise BUILD_BUG_ON triggers (obvious misuses are better than
mysterious ones).

Anyway heres a baseline, of existing prdbg use.
Each callsite costs 56 bytes of kernel .data
amdgpu has "extra" prdbgs due to macro expansion.
(see repeating linenos in control)
(it also has substantial use of drm.debug)
- tedious fix but clear size payoff, as a separate patch, later.

bash-5.1# for m in i915 amdgpu nouveau; do modprobe $m; done
dyndbg:   1 debug prints in module drm
dyndbg:   2 debug prints in module ttm
dyndbg:   8 debug prints in module video
dyndbg: 167 debug prints in module i915
dyndbg: 2339 debug prints in module amdgpu
dyndbg:   3 debug prints in module wmi
dyndbg:   3 debug prints in module nouveau

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
 drivers/gpu/drm/amd/amdgpu/Makefile           |  2 +
 .../gpu/drm/amd/display/dc/core/dc_debug.c    | 43 ++++++++++++++++++-
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index c56320e78c0e..1f084919294c 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -38,6 +38,8 @@ ccflags-y := -I$(FULL_AMD_PATH)/include/asic_reg \
 	-I$(FULL_AMD_DISPLAY_PATH)/amdgpu_dm \
 	-I$(FULL_AMD_PATH)/amdkfd
 
+ccflags-$(CONFIG_DYNAMIC_DEBUG_CORE) += -DYNAMIC_DEBUG_MODULE
+
 amdgpu-y := amdgpu_drv.o
 
 # add KMS driver
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_debug.c b/drivers/gpu/drm/amd/display/dc/core/dc_debug.c
index 21be2a684393..ae462e5d42c6 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_debug.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_debug.c
@@ -36,8 +36,49 @@
 
 #include "resource.h"
 
-#define DC_LOGGER_INIT(logger)
+#ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG
+/* define a drm.debug style dyndbg pr-debug control point */
+#include <linux/dynamic_debug.h>
+
+unsigned long __debug_dc;
+EXPORT_SYMBOL(__debug_dc);
+
+#define help_(_N, _cat)	"\t  Bit-" #_N "\t" _cat "\n"
+
+#define DC_DYNDBG_BITMAP_DESC(name)					\
+	"Control pr_debugs via /sys/module/amdgpu/parameters/" #name	\
+	", where each bit controls a debug category.\n"			\
+	help_(0, "[SURFACE]:")						\
+	help_(1, "[CURSOR]:")						\
+	help_(2, "[PFLIP]:")						\
+	help_(3, "[VBLANK]:")						\
+	help_(4, "[HW_LINK_TRAINING]:")				\
+	help_(5, "[HW_AUDIO]:")					\
+	help_(6, "[SCALER]:")						\
+	help_(7, "[BIOS]:")						\
+	help_(8, "[BANDWIDTH_CALCS]:")					\
+	help_(9, "[DML]:")						\
+	help_(10, "[IF_TRACE]:")					\
+	help_(11, "[GAMMA]:")						\
+	help_(12, "[SMU_MSG]:")
+
+DEFINE_DYNAMIC_DEBUG_CATEGORIES(debug_dc, __debug_dc,
+				DC_DYNDBG_BITMAP_DESC(debug_dc),
+				_DD_cat_(0, "[CURSOR]:"),
+				_DD_cat_(1, "[PFLIP]:"),
+				_DD_cat_(2, "[VBLANK]:"),
+				_DD_cat_(3, "[HW_LINK_TRAINING]:"),
+				_DD_cat_(4, "[HW_AUDIO]:"),
+				_DD_cat_(5, "[SCALER]:"),
+				_DD_cat_(6, "[BIOS]:"),
+				_DD_cat_(7, "[BANDWIDTH_CALCS]:"),
+				_DD_cat_(8, "[DML]:"),
+				_DD_cat_(9, "[IF_TRACE]:"),
+				_DD_cat_(10, "[GAMMA]:"),
+				_DD_cat_(11, "[SMU_MSG]:"));
+#endif
 
+#define DC_LOGGER_INIT(logger)
 
 #define SURFACE_TRACE(...) do {\
 		if (dc->debug.surface_trace) \
-- 
2.31.1