Re: Emacs-26.0.91: switch-to-buffer-other-window runs too slowly (about 0.1s)

[martin rudalics]

> It seems to me that if FRAME_VISIBLE_P can return non-zero when a
> frame is not visible, we are toast anyhow, because we have no
> reasonable way of telling whether a frame is or isn't visible.
> Waiting for 100 msec is not a guarantee for having the frame visible
> afterwards, certainly not if we don't make sure it is so at the end of
> the wait.
>
> So I'd like to see some evidence of such grave problems, before we go
> on with such a problematic assumption.

All I meant was that if FRAME_VISIBLE_P says that the frame is visible
we should use that and we will find out soon enough if it doesn't tell
us the truth.

> FWIW, the original wait loop did use FRAME_VISIBLE_P as an indication
> of whether we need the wait at all: it would not enter the loop if
> FRAME_VISIBLE_P returned non-zero.

So x_make_frame_visible should not enter the loop when FRAME_VISIBLE_P
returns non-zero but cannot rely on FRAME_VISIBLE_P to return non-zero
in order to decide whether it's safe to leave the loop.

martin