CONFIG_DRM_USE_DYNAMIC_DEBUG=y has a regression, due to a chicken-egg
initialization problem:
1- modprobe i915
i915 needs drm.ko, which is loaded 1st
2- "modprobe drm drm.debug=0x1ff" (virtual/implied)
drm.debug is set post-initialization, from boot-args etc
3- `modprobe i915` finishes
W/O drm.debug-on-dyndbg that just works, because drm_dbg* does
drm_debug_enabled() to check __drm_debug & DRM_UT_<CAT> before
printing.
But the whole point of CONFIG_DRM_USE_DYNAMIC_DEBUG is to avoid that
runtime test, by enabling (at end/after module_init) a static-key at
selected callsites in the just-loaded module.
And since drm.ko is loaded before all dependent modules, no other
modules are "just-loaded", and their drm.debug callsites are not
present yet, just those in drm.ko itself.
CC: <ville.syrj...@linux.intel.com>
Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
.v2 - default=N, cuz CI tests BROKEN stuff too. @ville.syrjala
---
drivers/gpu/drm/Kconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 34f5a092c99e..5adc8d5b6a40 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -53,7 +53,8 @@ config DRM_DEBUG_MM
config DRM_USE_DYNAMIC_DEBUG
bool "use dynamic debug to implement drm.debug"
- default y
+ default n
+ depends on BROKEN # chicken-egg initial enable problem
depends on DRM
depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
depends on JUMP_LABEL
--
2.38.1
