Troubleshooting xrandr - Can't get proper dual-screen

[Sebastian Redl]

Hi,

I just switched to the open-source radeon driver, but now I can't get 
dual-screen to work properly.

My system is a Kubuntu 9.04 64-bit using a 2.6.28-13 kernel. The X 
server is 1.6.0-0ubuntu14, radeon_drv.so says its module version is 
6.12.1. My xorg.conf is a Kubuntu stock configuration, i.e. pretty much 
empty, except for an added Virtual line setting the virtual size to 
2560x1024 (two 1280x1024 side-by-side).

My rather troublesome video card is a RV516-based AGP no-name card 
advertising itself as

RADEON(0): Chipset: "ATI Radeon X1300/X1550" (ChipID = 0x7187)
RADEON(0): ATOM BIOS Rom:
        SubsystemVendorID: 0x174b SubsystemID: 0x3000
        IOBaseAddress: 0xa000
        Filename: JC8513SA.002
        BIOS Bootup Message:
X1550 Rialto 256mb DDR2 BIOS 550e/400m Channel AB

The problem is this: the two screens are detected and xrandr advertises 
them:

$ xrandr
Screen 0: minimum 320 x 200, current 2560 x 1024, maximum 2560 x 1024
VGA-0 connected 1280x1024+1280+0 (normal left inverted right x axis y 
axis) 338mm x 270mm
   1280x1024      60.0*+   75.0     60.0*
   1152x864       75.0
   1024x768       75.0     70.1     60.0
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   640x480        75.0     72.8     66.7     59.9
   720x400        70.1
DVI-0 connected 1280x1024+1280+0 (normal left inverted right x axis y 
axis) 338mm x 270mm
   1280x1024      60.0*+
   1152x864       75.0
   1024x768       75.0     70.1     60.0
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   640x480        75.0     72.8     66.7     59.9
   720x400        70.1

However, they are in clone-screen mode. I attempt to put them in proper 
side-by-side mode:

$ xrandr --output VGA-0 --right-of DVI-0

This first does nothing for several seconds, then both screens go black 
for a moment, then come back the way they were before - definitely not 
giving me more workspace. The same thing happens if I swap the outputs 
in the command.

The output detection in the log looks like this:

(II) RADEON(0): Output VGA-0 using monitor section Configured Monitor
(II) RADEON(0): I2C bus "VGA-0" initialized.
(II) RADEON(0): Output DVI-0 has no monitor section
(II) RADEON(0): I2C bus "DVI-0" initialized.
(II) RADEON(0): Port0:
  XRANDR name: VGA-0
  Connector: VGA
  CRT1: INTERNAL_KLDSCP_DAC1
  DDC reg: 0x7e40
(II) RADEON(0): Port1:
  XRANDR name: DVI-0
  Connector: DVI-I
  CRT2: INTERNAL_KLDSCP_DAC2
  DFP3: INTERNAL_LVTM1
  DDC reg: 0x7e50

It seems a bit as if xrandr can't tell my outputs apart, though: if I 
try to change something about just one screen, say change the resolution 
or put it upside down:

$ xrandr --output VGA-0 --mode 1024x768
$ xrandr --output VGA-0 --rotate inverted

it always affects both screens, not just the one I select.


I'll do anything necessary to help track down this problem. I can't work 
with a single screen, I'm spoiled. Please tell me what to do.

The full gzipped X log is attached.

Sebastian
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