Re: [Ksummit-discuss] [TECH TOPIC] printk redesign

[Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>]

On (06/23/17 11:07), Bartlomiej Zolnierkiewicz wrote:
> On Thursday, June 22, 2017 03:48:34 PM Daniel Vetter wrote:
> > On Thu, Jun 22, 2017 at 3:42 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > > Tears pretty much guaranteed, and after a few hacks from Alan&me I
> > > concluded that the only way to fix this is to at least partially
> > > rewrite fbdev (a dead subsystem, so no one's volunteering), with the
> > > risk that you get to revert it all because someone is indeed relying
> > > on that super-flexible module loading order sequence. The simplest fix
> > > would probably be to make the entire fbdev->fbcon setup depency a
> > > hard-coded function call, or maybe at most a one-shot symbol_get
> > > attempt.
> > 
> > I did once hash out a plan how to fix this with the least amount of pain:
> > 
> > 1. Merge a patch to build the fbcon support into the overall fb.ko
> > module, so that the dynamic loading nonsense is essentially disabled,
> > and fbcon becomes a Kconfig/compile-time only option, no longer a
> > runtime-selectable thing.
> > 
> > 2. Wait 1 year and pray that no one reports a regression. If you're
> > unlucky, try to fence them of with a runtime option to disable fbcon.
> > 
> > 3. Rip out the notifier nonsense and replace it by direct function
> > calls. You can only do that once 1. won't be reverted anymore.
> > 
> > 4. Push the console_lock donw the callchains until it's again at the
> > right spots, auditing all the other stuff meanwhile to make sure the
> > locking is still correct.
> > 
> > 5. Apply your patch to make console_lock sane.
> > 
> > Adding fbdev maintainers and lists just.
> 
> Your plan sounds good to me.

cool.

I'm willing to help. let's coordinate.

	-ss