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Bug 439840

Summary: x11-drivers/xf86-video-savage - EXA acceleration problems
Product: Gentoo Linux Reporter: Riccardo <multix>
Component: Current packagesAssignee: Gentoo X packagers <x11>
Severity: major    
Priority: Normal    
Version: unspecified   
Hardware: x86   
OS: Linux   
Package list:
Runtime testing required: ---

Description Riccardo 2012-10-27 10:25:59 UTC
Since switching to EXA (XAA stopped working and displayed garbage) on a S3 savage card

01:00.0 VGA compatible controller: S3 Inc. SuperSavage IX/C SDR (rev 05) 

when running xorg (Latest version installed: 1.13.0) using x11-drivers/xf86-video-savage (Latest version installed: 2.3.6) I have two major problems:

1) ridiculous 2D performance: moving windows around, scrolling xterm is incredibly slow, like vnc over a slow connection! (Using WindowMaker, not fancy desktops)

2) when exiting X11, the framebuffer of the console is ruined: it remains black, all consoles are black. The respond to typing (machine is not locked) but black
Comment 1 Matt Turner gentoo-dev 2012-10-27 17:35:46 UTC
It's outside of our scope to solve this. It's better to report this upstream ( instead.
Comment 2 Chí-Thanh Christopher Nguyễn gentoo-dev 2012-10-27 20:46:47 UTC
xorg-server-1.13 no longer supports XAA. The garbage you were seeing are probably bugs in shadowfb which is the default fallback.

If framebuffer console is messed up, try a different fb driver (vesafb, uvesafb, savagefb, vga16fb) or vga text mode.

Regarding the EXA slowness, try to play with the EXA options in xorg.conf (see "man exa"). Other than that you will need to wait until upstream fixes this and stay with xorg-server-1.12 in the meantime.
Comment 3 Riccardo 2012-11-04 09:43:29 UTC
I tried switching back to xorg 12.4 (and rebuilding all dirvers/modules again due to ABI downgrade) and noticed two things:

1) still with EXA enabled, I experience 2D slowness, however at xserver termination, my framebuffer is fine again

2) with XAA enabled everything works smooth again, both 2D performance and console after exit

point 1 proves that the console mess-up problem is not EXA/XAA related, but xorg related
Comment 4 Chí-Thanh Christopher Nguyễn gentoo-dev 2012-11-04 09:44:15 UTC
The EXA slowness can still be due to your fb driver.
Comment 5 Riccardo 2012-11-04 09:50:33 UTC
What/where do you suggest a change? are you sepaking about xorg settings? currently I have

        Identifier  "Card0"
        Driver      "savage"
        VendorName  "S3 Inc."
        BoardName   "SuperSavage IX/C SDR"
        BusID       "PCI:1:0:0"
        #Option      "AccelMethod" "XAA"
        Option      "AccelMethod" "EXA"

at a forum suggestion I had added
       Option "MigrationHeuristic" "greedy"

without success.

It is interesting to read:
       The EXA architecture is designed to make accelerating the Render exten-
       sion simple and efficient, and results in various performance tradeoffs
       compared to XAA. 

if it is efficient, it shouldn't have a performance tradeoff .)
Comment 6 Chí-Thanh Christopher Nguyễn gentoo-dev 2012-11-04 09:55:04 UTC
The first change I suggest is to lose that fb driver (or replace it with one of the others).

The other changes are the four EXA options, which you can try in multiple combinations to see if there is one combination that makes things work faster.

Also don't forget to report this issue at, because we are just packaging what upstream releases.
Comment 7 Chí-Thanh Christopher Nguyễn gentoo-dev 2013-09-25 16:34:19 UTC
Please test 2.3.7 and if the issue still exists, reopen with a link to the upstream bug report.