https://github.com/torvalds/linux
Revision bb2ff6c27bc9e1da4d3ec5e7b1d6b9df1092cb5a authored by Ville Syrjälä on 07 February 2023, 14:33:37 UTC, committed by Jani Nikula on 13 February 2023, 16:23:04 UTC
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
1 parent 7484a5b
History
Tip revision: bb2ff6c27bc9e1da4d3ec5e7b1d6b9df1092cb5a authored by Ville Syrjälä on 07 February 2023, 14:33:37 UTC
drm: Disable dynamic debug as broken
Tip revision: bb2ff6c
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