On Tue, 14 Jan 2020 12:21:43 -0500 Sean Paul <sean@xxxxxxxxxx> wrote: > From: Sean Paul <seanpaul@xxxxxxxxxxxx> > > This patch uses a ring_buffer to keep a "flight recorder" (name credit Weston) > of DRM logs for a specified set of debug categories. The user writes a > bitmask of debug categories to the "trace_mask" node and can read log > messages from the "trace" node. > > These nodes currently exist in debugfs under the dri directory. I > intended on exposing all of this through tracefs originally, but the > tracefs entry points are not exposed, so there's no way to create > tracefs files from drivers at the moment. I think it would be a > worthwhile endeavour, but one requiring more time and conversation to > ensure the drm traces fit somewhere sensible. You may want to rebase these on my tree that renames ring_buffer to trace_buffer. For more information, read this thread: https://lore.kernel.org/r/20191213153553.GE20583@krava My tree is currently being tested and when it finishes contingent on no errors found, I'll be pushing it to linux-next. https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git/commit/?h=ftrace/core&id=13292494379f92f532de71b31a54018336adc589 -- Steve > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > Cc: David Airlie <airlied@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx> > Cc: Rob Clark <robdclark@xxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> > Link: https://patchwork.freedesktop.org/patch/msgid/20191010204823.195540-1-sean@xxxxxxxxxx #v1 > Link: https://lists.freedesktop.org/archives/dri-devel/2019-November/243230.html #v2 > Link: https://patchwork.freedesktop.org/patch/msgid/20191212203301.142437-1-sean@xxxxxxxxxx #v3 > > Changes in v2: > - Went with a completely different approach: > https://lists.freedesktop.org/archives/dri-devel/2019-November/243230.html > > Changes in v3: > - Changed commit message to be a bit less RFC-y > - Make class_drm_category_log an actual trace class > > Changes in v4: > - Instead of [ab]using trace events and the system trace buffer, use our > own ringbuffer > ---
