Bug#790663: Extremely slow window dragging and very poor performance with KMS activated on RV100/M6 [Rage/Radeon Mobility Series]

Alfonso García alfon.gz at gmail.com
Wed Jul 1 09:39:50 PDT 2015

Hi, thanks for respond so quickly.

In resume: The only thing give me an usable X environment is the following

Option "Accel" "off"

This way I can work decently but not faster than with previous version
(Debian 7)

A detail that I forget to include is that I work with an external monitor
controlled by xrandr. When I start the X window system (writting "startx")
both screens are twins (it shows the same with the same resolution).  The
problem comes when I turn off LVDS and get the VGA maximum resolution:

xrandr --output VGA-0 --auto --mode 1920x1080

NOTE: I insists that with the previous version of driver (Debian 7) I didn't
have any problem, all works fine. All stop working with the upgrade.

If you need additional information, please feel free to ask

Thank you for you time.

I respond on your message below...

On 01/07/15, Michel Dänzer wrote:
> On 01.07.2015 01:44, alfon wrote:
> > 
> > Section "Extensions"
> > 	Option		"Composite"		"Disable"
> > EndSection
> Why are you disabling this? If the desktop environment (DE) you're using
> (which is it?) supports compositing, that might alleviate the problem.

I really don't know why I disabled this, I just was proving different

I'm working with the OpenBox window manager.

> > Section "ServerFlags"
> > 	Option          "AIGLX"                 "off"
> >         Option          "DRI2"			"off"
> > EndSection
> Disabling AIGLX isn't a good idea either. I don't think Option "DRI2"
> has any effect.
> > 	Option          "EXAVSync"              "on"
> [...]
> > 	Option 		"ColorTiling"		"off"
> > 	Option 		"ColorTiling2D" 	"off"
> > 	Option          "EXAPixmaps"            "on"
> Does commenting out these options help?

No, the only thing that help something is turned off accel:

Option "Accel" "off"

If I do that, I can get an usable X environment. Which it is paradoxical, because I'm working without graphic acceleration

> > 	Option		"EnablePageFlip"	"off"
> I recommend against disabling this.
> > 		Virtual         2944 1080
> This Virtual directive is unnecessary with KMS and causes the driver to
> allocate at least twice as much VRAM as necessary for the front buffer.
> Please try commenting it out.

I follow your recommendation, but with no perceptible effects

> > If I turn off hardware acceleration, the X environment is usable but still
> > more slow than I used in UMS mode. In UMS mode (option radeon modeset=0)
> > the Xorg window system directly crash
> The Xorg radeon driver doesn't support UMS anymore.
> -- 
> Earthling Michel Dänzer               |               http://www.amd.com
> Libre software enthusiast             |             Mesa and X developer

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