Re: [RFC 0/5] Introduce NMI aware serial drivers

[Daniel Thompson]

On Thu, Aug 13, 2020 at 02:55:12PM +0530, Sumit Garg wrote:
> On Thu, 13 Aug 2020 at 05:38, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> > On Wed, Aug 12, 2020 at 8:27 AM Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> > > One
> > > last worry is that I assume that most people testing (and even
> > > automated testing labs) will either always enable NMI or won't enable
> > > NMI.  That means that everyone will be only testing one codepath or
> > > the other and (given the complexity) the non-tested codepath will
> > > break.
> > >
> 
> The current patch-set only makes this NMI to work when debugger (kgdb)
> is enabled which I think is mostly suitable for development
> environments. So most people testing will involve existing IRQ mode
> only.
> 
> However, it's very much possible to make NMI mode as default for a
> particular serial driver if the underlying irqchip supports it but it
> depends if we really see any production level usage of NMI debug
> feature.

The effect of this patch is not to make kgdb work from NMI it is to make
(some) SysRqs work from NMI. I think that only allowing it to deploy for
kgdb users is a mistake.

Having it deploy automatically for kgdb users might be OK but it seems
sensible to make this feature available for other users too.

Daniel.