Bug#697727: xserver-xorg-video-radeon: [radeon] Scrolling in xterm slow with KMS
tilo at tilo-schwarz.de
Thu Jan 10 03:33:23 PST 2013
On Thu, 10 Jan 2013 10:34:07 +0100, Michel Dänzer <daenzer at debian.org>
> On Don, 2013-01-10 at 10:14 +0100, Tilo Schwarz wrote:
>> On Thu, 10 Jan 2013 09:16:37 +0100, Michel Dänzer <daenzer at debian.org>
>> > On Mit, 2013-01-09 at 20:01 +0100, Tilo Schwarz wrote:
>> >> Indeed, using
>> >> % grep ColorTiling /etc/X11/xorg.conf
>> >> Option "ColorTiling" "off"
>> >> the scrolling is twice as fast as without this option (from 12sec
>> >> to
>> >> 6sec). That is still almost three times slower than without KMS, but
>> >> already much more usable!
>> > The better solution would be to configure your terminals to use
>> > fontconfig/Xft for text rendering.
>> Do you have a link to "the correct debian way" to enable fontconfig/Xft
>> for text rendering? (Me being no X11 expert ...)
> It's app/toolkit specific. E.g. with xterm you can enable it with -fa
> and related options.
>> Is it a fontcontig and Xft, or is it a either fontcontig or Xft?
> It's mainly about Xft. Most users of that also use fontconfig for
> selecting the fonts to use, but that's not required.
> Most apps/toolkits have used the modern text rendering infrastructure by
> default for a long time, but a lot of terminal emulators are still
> holding out for some reason.
Thanks a lot for your help! It lead me to a nice workaround (even if the
original question KMS=0 vs. KMS=1 is not really solved by this).
The only thing I did (after reading about Xft and fontconfig) was to
install rxvt-unicode, which has xft support.
Running "time seq 100000" with various terminal/font combinations gives:
xterm -fn 9x15:
xterm -fa 9x15:
So for some reason urxvt seems to use a font path, which is as fast as the
speed having lenny installed. The Xresources for this test were:
% cat .Xresources
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