Subject: bug#148: [Bernardo Dal Seno]: scroll-margin and scroll-preserve-screen-position cause refresh problem

From: Stefan Monnier <[email-masked]>
Date: Mon, 21 Apr 2008 07:44:46 -0400

>> This behavior is not a bug in itself, it's just a symptom: it means that
>> redisplay was interrupted by user input before it had time
>> to terminate.  See redisplay-dont-pause.

> Okay, maybe the submitter of the Debian bug should set
> redisplay-dont-pause to t to work around the problem.

Yes, that should work around the problem.

>> So, the problem you're reporting is that Emacs's redisplay is too slow
>> to keep up with the scrolling (which is indeed a problem).  This may of
>> course depend on the file's content and the major-mode (since part of the
>> redisplay time might be used by font-locking, for example).

> Do you have an explanation why the combination of

> (setq scroll-margin 2)
> (setq scroll-preserve-screen-position)

> slows down redisplay so much on C-v, especially if point is in the
> middle of the window?  I've never seen the problem in the default
> settings.

I do not have an explanation, no.

        Stefan