[0/4] drm/i915/dmc_wl: Introduce debugfs interface

Message

Gustavo Sousa Jan. 17, 2025, 10:06 p.m. UTC

The DMC wakelock code needs to keep track of register offsets that need
the wakelock for proper access. If one of the necessary offsets are
missed, then the failure in asserting the wakelock is very likely to
cause problems down the road.

A miss could happen for at least two different reasons:

- We might have forgotten to add the offset (or range) to the relevant
  tables tracked by the driver in the first place.

- Or updates to either the DMC firmware or the display IP that require
  new offsets to be tracked and we fail to realize that.

To help capture these cases, let's introduce a debugfs interface for the
DMC wakelock. The debugfs exports a file for looking up untracked
offsets and another for defining extra ranges to be tracked by our
driver during runtime, without the need of edit+re-compile+re-load
cycle.

See the added documentation and commit message for details.

Gustavo Sousa (4):
  drm/i915/dmc_wl: Pass offset instead of reg to range table iterator
  drm/i915/dmc_wl: Add debugfs for untracked offsets
  drm/i915/dmc_wl: Add extra_ranges debugfs
  drm/i915/dmc_wl: Enable the debugfs only with enable_dmc_wl_debugfs=1

 drivers/gpu/drm/i915/Makefile                 |   1 +
 .../drm/i915/display/intel_display_debugfs.c  |   2 +
 .../drm/i915/display/intel_display_params.c   |   5 +
 .../drm/i915/display/intel_display_params.h   |   1 +
 drivers/gpu/drm/i915/display/intel_dmc_wl.c   |  23 +-
 drivers/gpu/drm/i915/display/intel_dmc_wl.h   |   2 +
 .../drm/i915/display/intel_dmc_wl_debugfs.c   | 517 ++++++++++++++++++
 .../drm/i915/display/intel_dmc_wl_debugfs.h   |  36 ++
 drivers/gpu/drm/xe/Makefile                   |   1 +
 9 files changed, 581 insertions(+), 7 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_dmc_wl_debugfs.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_dmc_wl_debugfs.h