core/conio.inc: when reading the serial port, drop read of IIR
authorH. Peter Anvin <hpa@zytor.com>
Mon, 18 May 2009 21:57:37 +0000 (14:57 -0700)
committerH. Peter Anvin <hpa@zytor.com>
Mon, 18 May 2009 21:57:37 +0000 (14:57 -0700)
commit3f00d3393230752919ba1f850d0e79901a67e64c
tree2ae06dc557c78c0918a54322890c6be9b5524998
parent8771b74ac9914ca32faa3d7f06a0bcfd8fa9bbd4
core/conio.inc: when reading the serial port, drop read of IIR

Drop the read of the IIR when reading the serial port.  First of all,
we weren't protecting AL so we clobbered the actual data; second of
all, this isn't actually necessary as reading RDR will clear the
interrupt condition per the UART spec.

It's worth noting that enabling interrupts here will do bad things if
the interrupts aren't edge-triggered (since we don't actually have an
interrupt routine to clear the interrupt condition); this also means
bad things will happen if the interrupt line is shared.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
core/conio.inc