[PATCH v2 1/3] drm: Add support for panic message output

[John Ogness]

On 2019-03-14, Daniel Vetter <daniel at ffwll.ch> wrote:
> That's why we came up with the trylock + immediate bail out design if
> that fails. Plus really only render the oops int whatever is the
> current display buffer, so that we don't have to do any hw programming
> at all.

I think this is your best option. The real work will be identifying
any/all spin locking that currently exists. For all of those, the code
needs to change to:

1. trylock if oops_in_progress, otherwise spinlock

2. if trylock fails, the code must have a sane failure

The 2nd point will be the difficult one. For example, you may have
functions without a return value taking spinlocks. But now those
functions could fail.

John Ogness