[PATCH v2 0/3] drm: Add panic handling

[Noralf Trønnes]

This patchset adds a way for DRM drivers to display kernel messages
during panic().

I had a Windows blue screen last year and remembered this patchset, so I
did a new version that I never got around to put out. Now that panic
handling came up on the ML, I'm sending it out as part of the discussion.

TODO:
Determine which part of the framebuffer that is actually visible. I
don't know enough about KMS to do this. See drm_panic_kmsg_render_screen().

Testing:
I have tested[1] using the formats and resolutions support by vc4 and
modetest. I have even recorded it[2]. RG24 and BG24 gave an unexpected
result, not sure what to make of it.

Noralf.

[1] https://gist.github.com/notro/b9fdff4c6a68a307091e970598f27ed0
[2] https://youtu.be/lZ80vL4dgpE
Version 1 (Aug 2016): https://patchwork.freedesktop.org/series/10867/

Changes since version 1:
- Use kernel message dumper
- Add multicolumn support
- Support some YUV formats
- cma: vmap PRIME buffers on import to support that case

Noralf Trønnes (3):
  drm: Add support for panic message output
  drm/cma-helper: Add support for panic screen
  drm/vc4: Support for panic screen

 drivers/gpu/drm/Kconfig              |   3 +
 drivers/gpu/drm/Makefile             |   2 +-
 drivers/gpu/drm/drm_drv.c            |   3 +
 drivers/gpu/drm/drm_fb_cma_helper.c  |  43 ++++
 drivers/gpu/drm/drm_framebuffer.c    | 117 +++++++++
 drivers/gpu/drm/drm_gem_cma_helper.c |   3 +
 drivers/gpu/drm/drm_internal.h       |   4 +
 drivers/gpu/drm/drm_panic.c          | 363 +++++++++++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_kms.c        |   3 +-
 include/drm/drm_fb_cma_helper.h      |   4 +-
 include/drm/drm_framebuffer.h        |  41 +++
 11 files changed, 583 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_panic.c

-- 
2.20.1