[SeaBIOS] Re: [PATCH] Fix serial port detection on systems with Blizzard Chrome EC

[Gerd Hoffmann]

On Mon, Mar 16, 2020 at 05:39:45PM +0100, Paul Menzel wrote:
> From: "Ronald G. Minnich" 
> Date: Thu, 24 May 2012 11:27:26 -0700
>
> Serial port detection in SeaBIOS tests for bit 2 in the IER. That bit is
> never set, and SeaBIOS mistakenly reports 0 serial ports. As it happens,
> just testing for IER to be not-all-ones is good enough.
>
> This happens on all systems where the AP serial port uses the Blizzard
> EC (Ivy Bridge, Haswell). Does not affect Bay Trail, since we use the
> native Intel serial port.

What is "AP serial port"?
> if (ier != 0x02)
> dprintf(8, "IER is 0x%02x (Expected 0x02 or 0x00)\n", ier);
> if (ier != 0x02 && ier != 0)
>     return 0;
> u8 iir = inb(port+SEROFF_IIR);
> if ((iir & 0x3f) != 0x02)
> dprintf(8, "IIR is 0x%02x (Expected != 0x3f)\n", iir & 0x3f);
> if ((iir & 0x3f) == 0x3f)

Looks reasonable to me.  Patch doesn't apply too.

cheers,
  Gerd