grabbing console (syscons) in kernel

[Andriy Gapon]

on 12/12/2011 00:06 Alexander Yerenkow said the following:
> 
> 
> 2011/12/11 Andriy Gapon <avg at freebsd.org <mailto:avg at freebsd.org>>
> 
> 
>     There are a few cases when the kernel needs to interact with a user via syscons.
>     This is the cases where the kernel not only spews some output but also expects
>     some input.  Some examples are:
>     - asking for a root filesystem specification
>     - entering ddb
>     - asking to press a key for reboot
> 
>     In this cases the kernel implicitly grabs the console for its own use.
>     I'd like to make action more explicit.
> 
>     What do you think about the approach and implementation in the following
>     patches?
>     Thank you!
> 
>     https://gitorious.org/~avg/freebsd/avgbsd/commit/5248b49ebf84d98a0597fa5aa4d813a38f581acc
>     https://gitorious.org/~avg/freebsd/avgbsd/commit/a0849c52242378474bb2eaa41726376fbc4c5bf6
>     https://gitorious.org/~avg/freebsd/avgbsd/commit/a67515cbd720b16f03ba435ed182966a8a338b15
>     https://gitorious.org/~avg/freebsd/avgbsd/commit/b8864b68b4c0e26ece065a38301c305833be32eb
>     https://gitorious.org/~avg/freebsd/avgbsd/commit/1017ae425d8abecd7482bd6c6deaaf9f25f5c6cd
> 
>     P.S. one of the benefits is that a keyboard is put into and out of the polling
>     mode before getting all the required input and after that; not around each
>     character as it is done now in rather twisted way.
> 
> 
> Does asking for geli password is such case too?

Yes.

> For example, I have mouse, which can disappear/reappear while laying still; and
> when geli asks password, ums0 connect message can appear, which moves line
> "Please enter geli password..." to top, and it can be missed;
> This behavior somehow change?

No.  The patches do not contain user-visible changes.  They make things easier
for keyboard drivers and hopefully provide a more logical interface to kernel.
Their primary target is the input path, they do not introduce any changes to the
output path.

-- 
Andriy Gapon