diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2022-02-24 14:24:25 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2022-02-28 09:58:42 +0100 |
| commit | 4db3189ce0621be901f249f8cd8226c977dd601d (patch) | |
| tree | 7e6a5434a75cedb789852116875b9b852de95266 /Documentation/gpu/todo.rst | |
| parent | 8c2d9bf5cbec8c81f1c2ada0c6864b60f5738e31 (diff) | |
drm/todo: Update panic handling todo
Some things changed, and add two useful links.
v2: Also include a link to the QR encoding work. Plus review from
Javier.
v3: Fix typo Guilherme spotted.
Reviewed-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: gpiccoli@igalia.com
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220224132425.3463791-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'Documentation/gpu/todo.rst')
| -rw-r--r-- | Documentation/gpu/todo.rst | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 1b2372ef4131..d6a7ebf717be 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -499,8 +499,12 @@ This is a really varied tasks with lots of little bits and pieces: achieved by using an IPI to the local processor. * There's a massive confusion of different panic handlers. DRM fbdev emulation - helpers have one, but on top of that the fbcon code itself also has one. We - need to make sure that they stop fighting over each another. + helpers had their own (long removed), but on top of that the fbcon code itself + also has one. We need to make sure that they stop fighting over each other. + This is worked around by checking ``oops_in_progress`` at various entry points + into the DRM fbdev emulation helpers. A much cleaner approach here would be to + switch fbcon to the `threaded printk support + <https://lwn.net/Articles/800946/>`_. * ``drm_can_sleep()`` is a mess. It hides real bugs in normal operations and isn't a full solution for panic paths. We need to make sure that it only @@ -512,16 +516,15 @@ This is a really varied tasks with lots of little bits and pieces: even spinlocks (because NMI and hardirq can panic too). We need to either make sure to not call such paths, or trylock everything. Really tricky. -* For the above locking troubles reasons it's pretty much impossible to - attempt a synchronous modeset from panic handlers. The only thing we could - try to achive is an atomic ``set_base`` of the primary plane, and hope that - it shows up. Everything else probably needs to be delayed to some worker or - something else which happens later on. Otherwise it just kills the box - harder, prevent the panic from going out on e.g. netconsole. +* A clean solution would be an entirely separate panic output support in KMS, + bypassing the current fbcon support. See `[PATCH v2 0/3] drm: Add panic handling + <https://lore.kernel.org/dri-devel/20190311174218.51899-1-noralf@tronnes.org/>`_. -* There's also proposal for a simplied DRM console instead of the full-blown - fbcon and DRM fbdev emulation. Any kind of panic handling tricks should - obviously work for both console, in case we ever get kmslog merged. +* Encoding the actual oops and preceding dmesg in a QR might help with the + dread "important stuff scrolled away" problem. See `[RFC][PATCH] Oops messages + transfer using QR codes + <https://lore.kernel.org/lkml/1446217392-11981-1-git-send-email-alexandru.murtaza@intel.com/>`_ + for some example code that could be reused. Contact: Daniel Vetter |