Re: [PATCH v5 5/6] drm/log: Implement suspend/resume

[John Ogness]

On 2024-11-04, Petr Mladek <pmladek@xxxxxxxx> wrote:
> I wonder whether console_start()/console_stop() should really
> manipulate CON_ENABLE flag. It might be historical solution when
> @console_suspended was a global variable.
>
> But it has changed with the commit 9e70a5e109a4a2336 ("printk: Add
> per-console suspended state").
>
> It might make more sense when console_start()/console_stop()
> manipulates CON_SUSPENDED flag. Then it would make sense
> to rename them suspend_this_console()/resume_this_console().

I worry about letting console drivers and printk.c both modify this flag
during normal runtime. One might clear CON_SUSPENDED too soon and cause
trouble.

CON_ENABLE and @console_suspended were always orthogonal. Moving
@console_suspended to CON_SUSPENDED did not change that relationship.

IMHO we should continue to keep them separate. But your point about the
console not being registered is a good one. We should update
console_stop()/console_start() to only operate on @console if it is
registered. Since those functions take the console_list_lock anyway, it
would be a simple change.

John