Xorg future (Was: Re: old radeon 7500 card, slow wm)

DJ Lucas dj at linuxfromscratch.org
Sat Sep 25 20:06:28 PDT 2010

On 09/23/2010 06:33 PM, Ken Moffat wrote:

>  With my essentially-LFS-6.7 desktop I'm noticing that if I have
> firefox open on one desktop, and something else in the same area on
> another, when I go back to firefox it takes a noticeable time to
> repaint itself, even if the processor was idle.  This is with
> xorg-server-1.9.  Compare to the 1.7-series servers where I only
> notice delays if I'm compiling something.
>  So, I looked at the thread that was pointed to.  I got quite
> confused by all the references to fglrx, but eventually picked the
> xserver-xorg-backclear.patch from Felix Kuehling [attached].  Was
> that what you were talking about ?

Yes.  IIUC, the patch that was added upstream creates about a 300ms
delay on resize of all windows on all devices because it reads back from
VRAM to get a bitmap to fill the area before the resize.  This is has a
very bad effect on fglrx drivers, but the same delay applies equally to
all devices.  The delay was what made the light bulb go on before.  This
applies to the 1.7 server as well, so this is definitely something
different WRT 1.9.

As far as xorg-server in the book, I'm sticking with 1.7.7 for now with
an R7.5-3 release which I plan to introduce tonight or tomorrow as it
has been tested thoroughly.  Unless somebody has a very compelling
reason to upgrade to xorg 7.6-pre, I'm not planning on putting 1.8.x
into the book at all as this was the version series slotted for R7.6.
It does look like 1.9 is slotted for R7.6 now according to
http://www.x.org/wiki/Releases/7.6 . I was under the impression that
1.8.x never finished the new input hotplugging code and they were
scrapping it for R7.6 (but that info is well over a year old now but
still seems current according to the above page).

I've cross-posted to BLFS-Dev.  Please continue this discussion there if
anyone thinks that 1.8 should be introduced. It'll take me a couple of
weeks more to test it as I want to put gnome on it and use it for a
while before commit.  I'm already very comfortable with what I had
suggested the other day for R7.5-3.  It's been running solid for months
on 6.6 and for a bit on a 6.7-pre, building tonight on real 6.7 with
errata (fixed pkg-config and autoconf, with patch applied to procps).

>  I applied it by hand to 1.9 [ also attached ] but it doesn't help.
> I'm not totally surprised, the main discussion in the thread pointed
> to by Thomas, apart from being for fglrx, seemed to be about a
> slowness in resizing windows (and from people using modern radeons).

Dang, though I had it figured out for ya. :-)

-- DJ Lucas

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