[gPXE] Fwd: interrupt and serial

[Stefan Hajnoczi]

On Tue, Feb 9, 2010 at 3:05 PM, Luca <lucarx76 at gmail.com> wrote:
> If I had interrupts, I could stop anything I'm doing every time I get a new
> character and put it into a buffer and then go back to what I'm doing. So I
> shouldn't miss any character.
> If I use polling, even if the loop is tight, if I get more characters while
> I'm in the loop, I might miss something (when I poll the serial might be too
> late).
> But I might be wrong so having the interrupts would not change the
> situation.

When I say a tight receive loop, I mean a loop that reads characters
from serial into memory.  The loop terminates once all data has been
received.  Execution of gPXE is blocked while this loop runs and
step() is not being called.

Have you implemented the serial code using a process - a step()
function that polls the serial port?  In this case I can imagine it
dropping characters.

Stefan