From: Ville Syrjälä ville.syrjala@linux.intel.com
commit bb2ff6c27bc9e1da4d3ec5e7b1d6b9df1092cb5a upstream.
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 Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Acked-by: Jim Cromie jim.cromie@gmail.com Acked-by: Maxime Ripard maxime@cerno.tech Signed-off-by: Jani Nikula jani.nikula@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20230207143337.2126678-1-jani.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 315cbdf61979..9abfb482b615 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 depends on DRM depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE depends on JUMP_LABEL