[v6,0/4] drm/panic: Add a QR code panic screen

Message

Jocelyn Falempe Aug. 12, 2024, 12:24 p.m. UTC

This series adds a new panic screen, with the kmsg data embedded in a QR code.

The main advantage of QR code, is that you can copy/paste the debug data to a bug report.

The QR code encoder is written in rust, and is very specific to drm panic.
The reason is that it is called in a panic handler, and thus can't allocate memory, or use locking.
The rust code uses a few rust core API, and provides only two C entry points.
There is no particular reason to do it in rust, I just wanted to learn rust, and see if it can work in the kernel.

If you want to see what it looks like, I've put a few screenshots here:
https://github.com/kdj0c/panic_report/issues/1

v2:
 * Rewrite the rust comments with Markdown (Alice Ryhl)
 * Mark drm_panic_qr_generate() as unsafe (Alice Ryhl)
 * Use CStr directly, and remove the call to as_str_unchecked()
   (Alice Ryhl)
 * Add a check for data_len <= data_size (Greg KH)

v3:
 * Fix all rust comments (typo, punctuation) (Miguel Ojeda)
 * Change the wording of safety comments (Alice Ryhl)
 * Add a link to the javascript decoder in the Kconfig (Greg KH)
 * Fix data_size and tmp_size check in drm_panic_qr_generate()

v4:
 * Fix the logic to find next line and skip the '\n' (Alic Ryhl)
 * Remove __LOG_PREFIX as it's not used (Alice Ryhl)

v5:
 * Move drm_panic_[init|exit]() prototype to drm_crtc_internal.h
   (Daniel Vetter)

v6:
 * rebase, and handle conflict with 5d45c01dea6f ("drm/panic: Add panic description")
 * Fix qr_width should be a signed int, to handle error code.

Jocelyn Falempe (4):
  drm/panic: Add integer scaling to blit()
  drm/rect: Add drm_rect_overlap()
  drm/panic: Simplify logo handling
  drm/panic: Add a QR code panic screen

 drivers/gpu/drm/Kconfig             |   31 +
 drivers/gpu/drm/Makefile            |    1 +
 drivers/gpu/drm/drm_crtc_internal.h |    4 +
 drivers/gpu/drm/drm_drv.c           |    3 +
 drivers/gpu/drm/drm_panic.c         |  340 +++++++--
 drivers/gpu/drm/drm_panic_qr.rs     | 1003 +++++++++++++++++++++++++++
 include/drm/drm_rect.h              |   15 +
 7 files changed, 1357 insertions(+), 40 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_panic_qr.rs


base-commit: 5d45c01dea6f9e0f2dbed3ffee02ac2e80579ad4