New subject: [Intel-gfx] [PATCH] drm: Disable dynamic debug as broken

7 Feb 2023

From: Ville Syrjälä ville.syrjala@linux.intel.com
CONFIG_DRM_USE_DYNAMIC_DEBUG breaks debug prints for (at least modular)
drm drivers. The debug prints can be reinstated by manually frobbing
/sys/module/drm/parameters/debug after the fact, but at that point the
damage is done and all debugs from driver probe are lost. This makes
drivers totally undebuggable.
There's a more complete fix in progress [1], with further details, but
we need this fixed in stable kernels. Mark the feature as broken and
disable it by default, with hopes distros follow suit and disable it as
well.
[1] https://lore.kernel.org/r/20230125203743.564009-1-jim.cromie@gmail.com
Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro")
Cc: Jim Cromie jim.cromie@gmail.com
Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org
Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com
Cc: Maxime Ripard mripard@kernel.org
Cc: Thomas Zimmermann tzimmermann@suse.de
Cc: David Airlie airlied@gmail.com
Cc: Daniel Vetter daniel@ffwll.ch
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Signed-off-by: Jani Nikula jani.nikula@intel.com
---
 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 f42d4c6a19f2..dc0f94f02a82 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -52,7 +52,8 @@ config DRM_DEBUG_MM
config DRM_USE_DYNAMIC_DEBUG
    bool "use dynamic debug to implement drm.debug"
-	default y
+	default n
+	depends on BROKEN
    depends on DRM
    depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
    depends on JUMP_LABEL
-- 
2.34.1


    