Some things changed, and add two useful links. v2: Also include a link to the QR encoding work. Plus review from Javier. Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx> Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx> Cc: gpiccoli@xxxxxxxxxx Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> --- Documentation/gpu/todo.rst | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 7bf7f2111696..2b1e7fa45603 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -475,8 +475,12 @@ 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 @@ -488,16 +492,15 @@ 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@xxxxxxxxxxx/>`_. -* 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 preceeding 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@xxxxxxxxx/>`_ + for some example code that could be reused. Contact: Daniel Vetter -- 2.34.1
