On Fri, 13 May 2022 at 22:09, Peter Delevoryas <p...@fb.com> wrote
> I was actually intentionally skipping that. If serial_hd(i)
> doesn’t exist, the function will return NULL.
>
> Chardev *serial_hd(int i)
> {
> assert(i >= 0);
> if (i < num_serial_hds) {
> return serial_hds[i];
> }
> return NULL;
> }
>
> So then, the serial device’s CharBackend’s “Chardev *chr”
> will be initialized as NULL. Looking at all of the
> usage of this attribute in “hw/char/serial.c”, I think
> that’s ok, the read/write functions will just be no-ops.
> They all have guards for “chr == NULL”.
Yes, this is deliberate. We added these in commit 12051d82f0040
because otherwise lots of board/SoC code would have to create
NullChardev dummy backends (or forget to and then crash depending
on the user's commandline).
thanks
-- PMM
