For CONFIG_DRM_USE_DYNAMIC_DEBUG=y, wrap drm_dbg() & drm_dev_dbg() in
one of dyndbg's Factory macros: _dynamic_func_call_no_desc().
This makes the (~4000) callsites controllable, typically by class:
# 0 is DRM_UT_CORE
#> echo module drm class 0 +p > /proc/dynamic_debug/control
=N: keeps direct forwarding: drm_*_dbg -> __drm_*_dbg()
I added the CONFIG_DRM_USE_DYNAMIC_DEBUG item because of the .data
footprint cost of per-callsite control; 56 bytes/site * ~2k,4k
callsites (for i915, amdgpu), which is significant enough that a user
might not want it. Using CONFIG_DYNAMIC_DEBUG_CORE only eliminates
the builtin portion, leaving only drm modules, but still 200k of
module data is a lot.
Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
drivers/gpu/drm/Kconfig | 12 ++++++++++++
drivers/gpu/drm/Makefile | 2 ++
include/drm/drm_print.h | 12 ++++++++++++
3 files changed, 26 insertions(+)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index b1f22e457fd0..ec14a1cd4449 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -63,6 +63,18 @@ config DRM_DEBUG_MM
If in doubt, say "N".
+config DRM_USE_DYNAMIC_DEBUG
+ bool "use dynamic debug to implement drm.debug"
+ default y
+ depends on DRM
+ depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+ depends on JUMP_LABEL
+ help
+ Use dynamic-debug to avoid drm_debug_enabled() runtime overheads.
+ Due to callsite counts in DRM drivers (~4k in amdgpu) and 56
+ bytes per callsite, the .data costs can be substantial, and
+ are therefore configurable.
+
config DRM_DEBUG_SELFTEST
tristate "kselftests for DRM"
depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 301a44dc18e3..24e6410d6c0e 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -3,6 +3,8 @@
# Makefile for the drm device driver. This driver provides support for the
# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
+CFLAGS-$(CONFIG_DRM_USE_DYNAMIC_DEBUG) += -DDYNAMIC_DEBUG_MODULE
+
drm-y := drm_aperture.o drm_auth.o drm_cache.o \
drm_file.o drm_gem.o drm_ioctl.o \
drm_drv.o \
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 4bed99326631..06f0ee06be1f 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -383,8 +383,14 @@ void __drm_dev_dbg(const struct device *dev, enum
drm_debug_category category,
} \
})
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
#define drm_dev_dbg(dev, cat, fmt, ...) \
__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+#else
+#define drm_dev_dbg(dev, cat, fmt, ...) \
+ _dynamic_func_call_no_desc(fmt, __drm_dev_dbg, \
+ dev, cat, fmt, ##__VA_ARGS__)
+#endif
/**
* DRM_DEV_DEBUG() - Debug output for generic drm code
@@ -491,7 +497,13 @@ void ___drm_dbg(enum drm_debug_category category, const
char *format, ...);
__printf(1, 2)
void __drm_err(const char *format, ...);
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
#define __drm_dbg(fmt, ...) ___drm_dbg(fmt, ##__VA_ARGS__)
+#else
+#define __drm_dbg(cat, fmt, ...) \
+ _dynamic_func_call_no_desc(fmt, ___drm_dbg, \
+ cat, fmt, ##__VA_ARGS__)
+#endif
/* Macros to make printk easier */
--
2.35.1
