On Mon, Feb 1, 2021 at 11:24 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> While it cures the problem on the reporters machine it breaks machines
> with Intel chipsets which use bit 0-5 of the D register. So check only
> for bit 6 being 0 which is the case on these Intel machines as well.
This looks fine, but it might also be worth it simply just checking
for the only really special value: 0xff, and going "ok, that looks
like missing hardware".
That's what a few other drivers historically do in their probing
routines, so it's not unheard of (ie you can find drivers doing that
kind of
/* If we read 0xff from the LSR, there is no UART here. */
if (inb(.. port ..) == 0xff)
in their init routines.
Not a big deal either way, I just think it would be more in like with
what other places do in similar situations
Linus
