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drm: Disable dynamic debug as broken

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.nikula@intel.com

authored by

Ville Syrjälä and committed by
Jani Nikula
bb2ff6c2 7484a5bc

+2 -1
+2 -1
drivers/gpu/drm/Kconfig
··· 53 53 54 54 config DRM_USE_DYNAMIC_DEBUG 55 55 bool "use dynamic debug to implement drm.debug" 56 - default y 56 + default n 57 + depends on BROKEN 57 58 depends on DRM 58 59 depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE 59 60 depends on JUMP_LABEL