@@ -62,6 +62,32 @@ 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
+ The "basic" drm.debug facility does a lot of unlikely
+ bit-field tests at runtime; while cheap individually, the
+ cost accumulates. DYNAMIC_DEBUG can patch pr_debug()s into
+ NOOP slots, in a running kernel, so avoids those bit-test
+ overheads, and is therefore recommended by default.
+
+ DRM_USE_DYNAMIC_DEBUG converts "basic" to "dyndbg", this
+ creates many new dyndbg callsites (56 bytes each), which
+ significantly increases drm* module .data, so is optional.
+ On an x86-64 kernel, with a config derived from fedora, that
+ price is:
+ #prdbgs KiB #with DRM_USE_DYNAMIC_DEBUG=y
+ kernel 3079 166k
+ drm 1 .06k 376 21k
+ drm_kms_helper 207 12k
+ i915 167 9.3k 1811 101k
+ amdgpu 2339 130k 3917 220k
+ nouveau 3 .17k 105 ~60k
+
config DRM_DEBUG_SELFTEST
tristate "kselftests for DRM"
depends on DRM
@@ -33,6 +33,8 @@ drm-$(CONFIG_PCI) += drm_pci.o
drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+ccflags-$(CONFIG_DRM_USE_DYNAMIC_DEBUG) += -DDYNAMIC_DEBUG_MODULE
+
obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
drm_vram_helper-y := drm_gem_vram_helper.o
@@ -38,7 +38,7 @@ ccflags-y := -I$(FULL_AMD_PATH)/include/asic_reg \
-I$(FULL_AMD_DISPLAY_PATH)/amdgpu_dm \
-I$(FULL_AMD_PATH)/amdkfd
-ccflags-$(CONFIG_DYNAMIC_DEBUG_CORE) += -DYNAMIC_DEBUG_MODULE
+ccflags-$(CONFIG_DRM_USE_DYNAMIC_DEBUG) += -DYNAMIC_DEBUG_MODULE
amdgpu-y := amdgpu_drv.o
@@ -28,9 +28,11 @@
#include <linux/stdarg.h>
#include <linux/io.h>
+#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
+#include <linux/dynamic_debug.h>
#include <drm/drm.h>
#include <drm/drm_drv.h>
@@ -40,19 +42,40 @@
* __drm_debug: Enable debug output.
* Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
*/
-unsigned int __drm_debug;
+unsigned long __drm_debug;
EXPORT_SYMBOL(__drm_debug);
-MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
-"\t\tBit 0 (0x01) will enable CORE messages (drm core code)\n"
-"\t\tBit 1 (0x02) will enable DRIVER messages (drm controller code)\n"
-"\t\tBit 2 (0x04) will enable KMS messages (modesetting code)\n"
-"\t\tBit 3 (0x08) will enable PRIME messages (prime code)\n"
-"\t\tBit 4 (0x10) will enable ATOMIC messages (atomic code)\n"
-"\t\tBit 5 (0x20) will enable VBL messages (vblank code)\n"
-"\t\tBit 7 (0x80) will enable LEASE messages (leasing code)\n"
-"\t\tBit 8 (0x100) will enable DP messages (displayport code)");
-module_param_named(debug, __drm_debug, int, 0600);
+#define DRM_DEBUG_DESC \
+"Enable debug output, where each bit enables a debug category.\n" \
+"\t\tBit 0 (0x01) will enable CORE messages (drm core code)\n" \
+"\t\tBit 1 (0x02) will enable DRIVER messages (drm controller code)\n" \
+"\t\tBit 2 (0x04) will enable KMS messages (modesetting code)\n" \
+"\t\tBit 3 (0x08) will enable PRIME messages (prime code)\n" \
+"\t\tBit 4 (0x10) will enable ATOMIC messages (atomic code)\n" \
+"\t\tBit 5 (0x20) will enable VBL messages (vblank code)\n" \
+"\t\tBit 7 (0x80) will enable LEASE messages (leasing code)\n" \
+"\t\tBit 8 (0x100) will enable DP messages (displayport code)."
+
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
+MODULE_PARM_DESC(debug, DRM_DEBUG_DESC);
+module_param_named(debug, __drm_debug, ulong, 0600);
+#else
+static struct dyndbg_bitdesc drm_dyndbg_bitmap[] = {
+ [0] = { DRM_DBG_CAT_CORE },
+ [1] = { DRM_DBG_CAT_DRIVER },
+ [2] = { DRM_DBG_CAT_KMS },
+ [3] = { DRM_DBG_CAT_PRIME },
+ [4] = { DRM_DBG_CAT_ATOMIC },
+ [5] = { DRM_DBG_CAT_VBL },
+ [6] = { DRM_DBG_CAT_STATE },
+ [7] = { DRM_DBG_CAT_LEASE },
+ [8] = { DRM_DBG_CAT_DP },
+ [9] = { DRM_DBG_CAT_DRMRES }
+};
+DEFINE_DYNAMIC_DEBUG_BITGRPS(debug, __drm_debug, DRM_DEBUG_DESC,
+ drm_dyndbg_bitmap);
+
+#endif
void __drm_puts_coredump(struct drm_printer *p, const char *str)
{
@@ -256,8 +279,8 @@ void drm_dev_printk(const struct device *dev, const char *level,
}
EXPORT_SYMBOL(drm_dev_printk);
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
- const char *format, ...)
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+ const char *format, ...)
{
struct va_format vaf;
va_list args;
@@ -278,9 +301,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
va_end(args);
}
-EXPORT_SYMBOL(drm_dev_dbg);
+EXPORT_SYMBOL(__drm_dev_dbg);
-void __drm_dbg(enum drm_debug_category category, const char *format, ...)
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
{
struct va_format vaf;
va_list args;
@@ -297,7 +320,7 @@ void __drm_dbg(enum drm_debug_category category, const char *format, ...)
va_end(args);
}
-EXPORT_SYMBOL(__drm_dbg);
+EXPORT_SYMBOL(___drm_dbg);
void __drm_err(const char *format, ...)
{
@@ -317,7 +317,7 @@ i915-y += intel_gvt.o
include $(src)/gvt/Makefile
endif
-ccflags-$(CONFIG_DYNAMIC_DEBUG_CORE) += -DDYNAMIC_DEBUG_MODULE
+ccflags-$(CONFIG_DRM_USE_DYNAMIC_DEBUG) += -DDYNAMIC_DEBUG_MODULE
obj-$(CONFIG_DRM_I915) += i915.o
obj-$(CONFIG_DRM_I915_GVT_KVMGT) += gvt/kvmgt.o
@@ -35,7 +35,7 @@
#include <drm/drm.h>
/* Do *not* use outside of drm_print.[ch]! */
-extern unsigned int __drm_debug;
+extern unsigned long __drm_debug;
/**
* DOC: print
@@ -252,15 +252,15 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
/**
* enum drm_debug_category - The DRM debug categories
*
- * Each of the DRM debug logging macros use a specific category, and the logging
- * is filtered by the drm.debug module parameter. This enum specifies the values
- * for the interface.
+ * The drm.debug logging API[1] has 10 enumerated categories of
+ * messages, issued by 3 families of macros: 10 drm_dbg_<CATs>, 8
+ * DRM_DEBUG_<CATs>, and 3 DRM_DEV_DEBUG_<CATs>.
*
* Each DRM_DEBUG_<CATEGORY> macro logs to DRM_UT_<CATEGORY> category, except
* DRM_DEBUG() logs to DRM_UT_CORE.
*
- * Enabling verbose debug messages is done through the drm.debug parameter, each
- * category being enabled by a bit:
+ * Enabling categories of debug messages is done through the drm.debug
+ * parameter, each category being enabled by a bit:
*
* - drm.debug=0x1 will enable CORE messages
* - drm.debug=0x2 will enable DRIVER messages
@@ -268,8 +268,8 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
* - ...
* - drm.debug=0x1ff will enable all messages
*
- * An interesting feature is that it's possible to enable verbose logging at
- * run-time by echoing the debug value in its sysfs node::
+ * It's possible to enable drm.debug logging at run-time by echoing
+ * the debug value in its sysfs node::
*
* # echo 0xf > /sys/module/drm/parameters/debug
*
@@ -319,6 +319,103 @@ enum drm_debug_category {
DRM_UT_DRMRES = 0x200,
};
+/**
+ * DOC: CONFIG_DRM_USE_DYNAMIC_DEBUG - using dyndbg in drm.debug
+ *
+ * In the "basic" drm.debug implementation outlined above, each time a
+ * drm-debug API[1] call is executed, drm_debug_enabled(cat) tests
+ * __drm_debug vs cat before printing.
+ *
+ * DYNAMIC_DEBUG (aka: dyndbg) patches pr_debug()s in^out of the
+ * running kernel, so it can avoid drm_debug_enabled() and skip lots
+ * of unlikely bit tests.
+ *
+ * dyndbg has no concept of category, but we can prepend a
+ * class-prefix string: "drm:core: ", "drm:kms: ", "drm:driver: " etc,
+ * to pr_debug's format (at compile time).
+ *
+ * Then control the category::
+ *
+ * # echo module drm format "^drm:core: " +p > control
+ * c: dynamic_debug_exec_queries("format '^drm:core: ' +p", "drm");
+ *
+ * To do this for "basic" | "dyndbg", adaptation adds some macro indirection:
+ *
+ * 0. use dyndbg support to define the bits => prefixes map, and creates sysfs node
+ *
+ * DEFINE_DYNAMIC_DEBUG_CATEGORIES(debug, __drm_debug,
+ * "drm.debug - overview",
+ * { [0] = "drm:core: " },
+ * { [1] = "drm:kms: " }, ...);
+ *
+ * 1. DRM_DBG_CAT_<CAT>
+ *
+ * This set of symbols replaces DRM_UT_<CAT> inside the drm-debug API;
+ * for "basic" it is a copy of DRM_UT_<CAT>, otherwise they are the set
+ * of class prefix strings used in pr_debugs (either directly or by
+ * macro wrappers).
+ *
+ * 2. drm_dev_dbg & drm_debug are called by drm.debug API
+ *
+ * These are now macros, either forwarding to renamed functions, or
+ * prepending the class string to the format, and invoking pr_debug
+ * directly. Since the API is all macros, dyndbg's pr_debug sees the
+ * actual (broad population of) callsites, and they're all
+ * individually controllable.
+ */
+#if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
+
+#define __drm_dbg(cls, fmt, ...) \
+ ___drm_dbg(cls, fmt, ##__VA_ARGS__)
+#define drm_dev_dbg(dev, cls, fmt, ...) \
+ __drm_dev_dbg(dev, cls, fmt, ##__VA_ARGS__)
+
+#define DRM_DBG_CAT_CORE DRM_UT_CORE
+#define DRM_DBG_CAT_DRIVER DRM_UT_DRIVER
+#define DRM_DBG_CAT_KMS DRM_UT_KMS
+#define DRM_DBG_CAT_PRIME DRM_UT_PRIME
+#define DRM_DBG_CAT_ATOMIC DRM_UT_ATOMIC
+#define DRM_DBG_CAT_VBL DRM_UT_VBL
+#define DRM_DBG_CAT_STATE DRM_UT_STATE
+#define DRM_DBG_CAT_LEASE DRM_UT_LEASE
+#define DRM_DBG_CAT_DP DRM_UT_DP
+#define DRM_DBG_CAT_DRMRES DRM_UT_DRMRES
+
+#else /* CONFIG_DRM_USE_DYNAMIC_DEBUG */
+
+/* join prefix + format in cpp so dyndbg can see it */
+#define __drm_dbg(pfx, fmt, ...) \
+ pr_debug(pfx fmt, ##__VA_ARGS__)
+#define drm_dev_dbg(dev, pfx, fmt, ...) \
+ dev_dbg(dev, pfx fmt, ##__VA_ARGS__)
+
+/**
+ * enum-ish DRM_DBG_CAT_<categories>::
+ *
+ * - DRM_DBG_CAT_CORE "drm:core: "
+ * - DRM_DBG_CAT_DRIVER "drm:drvr: "
+ * - DRM_DBG_CAT_KMS "drm:kms: "
+ * - DRM_DBG_CAT_PRIME "drm:prime: "
+ * - DRM_DBG_CAT_ATOMIC "drm:atomic: "
+ * - DRM_DBG_CAT_VBL "drm:vbl: "
+ * - DRM_DBG_CAT_STATE "drm:state: "
+ * - DRM_DBG_CAT_LEASE "drm:lease: "
+ * - DRM_DBG_CAT_DP "drm:dp: "
+ * - DRM_DBG_CAT_DRMRES "drm:res: "
+ */
+#define DRM_DBG_CAT_CORE "drm:core: "
+#define DRM_DBG_CAT_DRIVER "drm:drvr: "
+#define DRM_DBG_CAT_KMS "drm:kms: "
+#define DRM_DBG_CAT_PRIME "drm:prime: "
+#define DRM_DBG_CAT_ATOMIC "drm:atomic: "
+#define DRM_DBG_CAT_VBL "drm:vbl: "
+#define DRM_DBG_CAT_STATE "drm:state: "
+#define DRM_DBG_CAT_LEASE "drm:lease: "
+#define DRM_DBG_CAT_DP "drm:dp: "
+#define DRM_DBG_CAT_DRMRES "drm:res: "
+
+#endif /* CONFIG_DRM_USE_DYNAMIC_DEBUG */
+
static inline bool drm_debug_enabled(enum drm_debug_category category)
{
return unlikely(__drm_debug & category);
@@ -334,8 +431,8 @@ __printf(3, 4)
void drm_dev_printk(const struct device *dev, const char *level,
const char *format, ...);
__printf(3, 4)
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
- const char *format, ...);
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+ const char *format, ...);
/**
* DRM_DEV_ERROR() - Error output.
@@ -383,6 +480,16 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
} \
})
+/**
+ * DRM debug API - library of macros to issue categorized syslog messages
+ *
+ * multiple flavors::
+ * - DRM_DEV_DEBUG<,_DRIVER,_KMS>
+ * - drm_dbg_<core,kms,prime,atomic,vbl,state,lease,dp,drmres> (prefer these)
+ * - DRM_DEBUG<,_DRIVER,_KMS,_PRIME,_ATOMIC,_VBL,_LEASE,_DP> (over these)
+ * - DRM_DEBUG_KMS_RATELIMITED
+ */
+
/**
* DRM_DEV_DEBUG() - Debug output for generic drm code
*
@@ -392,7 +499,7 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
* @fmt: printf() like format string.
*/
#define DRM_DEV_DEBUG(dev, fmt, ...) \
- drm_dev_dbg(dev, DRM_UT_CORE, fmt, ##__VA_ARGS__)
+ drm_dev_dbg(dev, DRM_DBG_CAT_CORE, fmt, ##__VA_ARGS__)
/**
* DRM_DEV_DEBUG_DRIVER() - Debug output for vendor specific part of the driver
*
@@ -402,7 +509,7 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
* @fmt: printf() like format string.
*/
#define DRM_DEV_DEBUG_DRIVER(dev, fmt, ...) \
- drm_dev_dbg(dev, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
+ drm_dev_dbg(dev, DRM_DBG_CAT_DRIVER, fmt, ##__VA_ARGS__)
/**
* DRM_DEV_DEBUG_KMS() - Debug output for modesetting code
*
@@ -412,7 +519,7 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
* @fmt: printf() like format string.
*/
#define DRM_DEV_DEBUG_KMS(dev, fmt, ...) \
- drm_dev_dbg(dev, DRM_UT_KMS, fmt, ##__VA_ARGS__)
+ drm_dev_dbg(dev, DRM_DBG_CAT_KMS, fmt, ##__VA_ARGS__)
/*
* struct drm_device based logging
@@ -454,27 +561,26 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
#define drm_err_ratelimited(drm, fmt, ...) \
__drm_printk((drm), err, _ratelimited, "*ERROR* " fmt, ##__VA_ARGS__)
-
#define drm_dbg_core(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_CORE, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_CORE, fmt, ##__VA_ARGS__)
#define drm_dbg(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_DRIVER, fmt, ##__VA_ARGS__)
#define drm_dbg_kms(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_KMS, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_KMS, fmt, ##__VA_ARGS__)
#define drm_dbg_prime(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_PRIME, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_PRIME, fmt, ##__VA_ARGS__)
#define drm_dbg_atomic(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_ATOMIC, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_ATOMIC, fmt, ##__VA_ARGS__)
#define drm_dbg_vbl(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_VBL, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_VBL, fmt, ##__VA_ARGS__)
#define drm_dbg_state(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_STATE, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_STATE, fmt, ##__VA_ARGS__)
#define drm_dbg_lease(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_LEASE, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_LEASE, fmt, ##__VA_ARGS__)
#define drm_dbg_dp(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_DP, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_DP, fmt, ##__VA_ARGS__)
#define drm_dbg_drmres(drm, fmt, ...) \
- drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_DRMRES, fmt, ##__VA_ARGS__)
+ drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_DBG_CAT_DRMRES, fmt, ##__VA_ARGS__)
/*
@@ -484,7 +590,7 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
*/
__printf(2, 3)
-void __drm_dbg(enum drm_debug_category category, const char *format, ...);
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
__printf(1, 2)
void __drm_err(const char *format, ...);
@@ -523,35 +629,35 @@ void __drm_err(const char *format, ...);
/* NOTE: this is deprecated in favor of drm_dbg_core(NULL, ...). */
#define DRM_DEBUG(fmt, ...) \
- __drm_dbg(DRM_UT_CORE, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_CORE, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg(NULL, ...). */
#define DRM_DEBUG_DRIVER(fmt, ...) \
- __drm_dbg(DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_DRIVER, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_kms(NULL, ...). */
#define DRM_DEBUG_KMS(fmt, ...) \
- __drm_dbg(DRM_UT_KMS, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_KMS, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_prime(NULL, ...). */
#define DRM_DEBUG_PRIME(fmt, ...) \
- __drm_dbg(DRM_UT_PRIME, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_PRIME, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_atomic(NULL, ...). */
#define DRM_DEBUG_ATOMIC(fmt, ...) \
- __drm_dbg(DRM_UT_ATOMIC, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_ATOMIC, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_vbl(NULL, ...). */
#define DRM_DEBUG_VBL(fmt, ...) \
- __drm_dbg(DRM_UT_VBL, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_VBL, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_lease(NULL, ...). */
#define DRM_DEBUG_LEASE(fmt, ...) \
- __drm_dbg(DRM_UT_LEASE, fmt, ##__VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_LEASE, fmt, ##__VA_ARGS__)
/* NOTE: this is deprecated in favor of drm_dbg_dp(NULL, ...). */
#define DRM_DEBUG_DP(fmt, ...) \
- __drm_dbg(DRM_UT_DP, fmt, ## __VA_ARGS__)
+ __drm_dbg(DRM_DBG_CAT_DP, fmt, ## __VA_ARGS__)
#define __DRM_DEFINE_DBG_RATELIMITED(category, drm, fmt, ...) \
({ \
@@ -559,7 +665,8 @@ void __drm_err(const char *format, ...);
const struct drm_device *drm_ = (drm); \
\
if (drm_debug_enabled(DRM_UT_ ## category) && __ratelimit(&rs_)) \
- drm_dev_printk(drm_ ? drm_->dev : NULL, KERN_DEBUG, fmt, ## __VA_ARGS__); \
+ drm_dev_dbg((drm_) ? (drm_)->dev : NULL, \
+ DRM_DBG_CAT_ ## category, fmt, ##__VA_ARGS__); \
})
#define drm_dbg_kms_ratelimited(drm, fmt, ...) \
drm's debug system writes 10 distinct categories of messages to syslog using a small API[1]: drm_dbg*(10 names), DRM_DEV_DEBUG*(3 names), DRM_DEBUG*(8 names). There are thousands of these callsites, each categorized in this systematized way. These callsites can be enabled at runtime by their category, each controlled by a bit in drm.debug (/sys/modules/drm/parameter/debug). In the current "basic" implementation, drm_debug_enabled() tests these bits in __drm_debug each time an API[1] call is executed; while cheap individually, the costs accumulate with uptime. This patch uses dynamic-debug with (required) jump-label to patch enabled callsites onto their respective NOOP slots, avoiding all runtime bit-checks of __drm_debug by drm_debug_enabled(). Dynamic debug has no concept of category, but we can emulate one by replacing enum categories with a set of prefix-strings; "drm:core:", "drm:kms:" "drm:driver:" etc, and prepend them (at compile time) to the given formats. Then we can use: # echo module drm format "^drm:core: " +p > control` to enable the whole category with one query. This conversion yields many new prdbg callsites: dyndbg: 207 debug prints in module drm_kms_helper dyndbg: 376 debug prints in module drm dyndbg: 1811 debug prints in module i915 dyndbg: 3917 debug prints in module amdgpu Each site costs 56 bytes of .data, which is a big increase for drm modules, so CONFIG_DRM_USE_DYNAMIC_DEBUG makes it optional. CONFIG_JUMP_LABEL is also required, to get the promised optimizations. The "basic" -> "dyndbg" switchover is layered into the macro scheme A. A "prefix" version of DRM_UT_<CATs> map, named DRM_DBG_CAT_<CATs> "basic": DRM_DBG_CAT_<CATs> <=== DRM_UT_<CATs>. Identity map. "dyndbg": #define DRM_DBG_CAT_KMS "drm:kms: " #define DRM_DBG_CAT_PRIME "drm:prime: " #define DRM_DBG_CAT_ATOMIC "drm:atomic: " DRM_UT_* are preserved, since theyre used elsewhere. Since the callback maintains its state in __drm_debug, drm_debug_enabled() will stay synchronized, and continue to work. We can address them separately if they are called enough to be worth fixing. B. drm_dev_dbg() & drm_debug() are interposed with macros basic: forward to renamed fn, with args preserved enabled: redirect to pr_debug, dev_dbg, with CATEGORY format catenated This is where drm_debug_enabled() is avoided. The prefix is prepended at compile-time, no category at runtime. C. API[1] uses DRM_DBG_CAT_<CAT>s The API already uses B, now it uses A too, instead of DRM_UT_<CAT>, to get the correct token type for "basic" and "dyndbg" configs. D. use DEFINE_DYNAMIC_DEBUG_CATEGORIES() This defines the map using DRM_CAT_<CAT>s, and creates the /sysfs bitmap to control those categories. CONFIG_DRM_USE_DYNAMIC_DEBUG is also used to adjust amdgpu, i915 makefiles to add -DDYNAMIC_DEBUG_MODULE; it includes the current CONFIG_DYNAMIC_DEBUG_CORE and is enabled by the user. LIMITATIONS: dev_dbg(etal) effectively prepends twice, category then driver-name, yielding format strings like so: bash-5.1# grep amdgpu: /proc/dynamic_debug/control | grep drm: | cut -d= -f2- _ "amdgpu: drm:core: fence driver on ring %s use gpu addr 0x%016llx\012" _ "amdgpu: drm:kms: Cannot create framebuffer from imported dma_buf\012" This means we cannot use anchored "^drm:kms: " to specify the category, a small loss of precision. Note that searching on "format ^amdgpu: " works, but this is less valuable, because the same can be done with "module amdgpu". NOTES: Because the dyndbg callback is keeping state in __drm_debug, it synchronizes with drm_debug_enabled() and its remaining users; the switchover should be transparent. Code Review is expected to catch the lack of correspondence between bit=>prefix definitions (the selector) and the prefixes used in the API[1] layer above pr_debug() I've coded the categories with trailing spaces. This excludes any sub-categories which might get added later. This convention protects any "drm:atomic:fail:" callsites from getting stomped on by `echo 0 > debug`. Other categories could differ, but we need some default. Dyndbg requires that the prefix be in the compiled-in format string; run-time prefixing evades callsite selection by category. pr_debug("%s: ...", __func__, ...) // not ideal Unfortunately __func__ is not a macro, and cannot be catenated at preprocess/compile time. If you want that, you might consider +mfl flags instead;) Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- v5: . use DEFINE_DYNAMIC_DEBUG_CATEGORIES in drm_print.c . s/DRM_DBG_CLASS_/DRM_DBG_CAT_/ - dont need another term . default=y in Kconfig entry - per @DanVet . move some commit-log prose to dyndbg commit . add-prototyes to (param_get/set)_dyndbg . more wrinkles found by <lkp@intel.com> . relocate ratelimit chunk from elsewhere v6: . add kernel doc . fix cpp paste, drop '#' v7: . change __drm_debug to long, to fit with DEFINE_DYNAMIC_DEBUG_CATEGORIES . add -DDYNAMIC_DEBUG_MODULE to ccflags if DRM_USE_DYNAMIC_DEBUG v8: . adapt to altered ^ insertion . add mem cost numbers to kconfig . kdoc improvements (I hope) --- drivers/gpu/drm/Kconfig | 26 +++++ drivers/gpu/drm/Makefile | 2 + drivers/gpu/drm/amd/amdgpu/Makefile | 2 +- drivers/gpu/drm/drm_print.c | 55 ++++++--- drivers/gpu/drm/i915/Makefile | 2 +- include/drm/drm_print.h | 175 ++++++++++++++++++++++------ 6 files changed, 210 insertions(+), 52 deletions(-)