On Thu, 24 Feb 2022 14:24:25 +0100 Daniel Vetter <daniel.vetter@xxxxxxxx> wrote: > 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(-) Acked-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> Thanks, pq > > 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 >
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