psm(4) & atkbdc(4) locking

[Warner Losh]

On Mon, May 8, 2017 at 12:33 PM, Vladimir Kondratyev
<vladimir at kondratyev.su> wrote:
> Hi All
>
> In order to implement evdev support in psm(4) driver I`m going to add
> mutexes to psm and atkbdc drivers and mark psm interrupt and cdev handlers
> MPSAFE.
> Atkbd(4) is depending on Giant like before.
>
> Locking of these drivers seems to be low-hanging fruit as spl() calls are
> still in place but it has not occurred.
>
> Does someone know why it is not done yet? For reasons other than "Nobody
> took care of it"?
> Any hidden traps?

Working rock-solid reliably in ddb(4) is what tripped me up when I
started down this path 10 years ago. Understanding all the rules for
that was a bridge too far for me given the time I had for the project
then. If you have that covered (I haven't looked at the diffs yet),
you're golden.

Warner

> Patches can be found here:
> https://reviews.freebsd.org/D10263 (atkbdc, serialize hw registers access)
> https://reviews.freebsd.org/D10264 (psm, serialize softc access, mark
> interrupt and cdev handlers MPSAFE)
>
> --
> WBR
> Vladimir Kondratyev
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