Fresh install of 12.04.1 LTS x86-64, Sapphire Flex HD6950 video card.
- I initally booted with one display connected, added the other four, and they all worked (cloned)
- I can set them to "Multi-display desktop" and get five independent displays, but each has its own Unity bars. (I eventually want to merge four of these into a single work area treated as one display)
- In pursuit of Xinerama, I set them to "Single Display Desktop (Multi-desktop)", which requires a restart. During the subsequent boot, X fails to start.
Interesting bit from the end of /var/log/Xorg.0.log :
[ 14.517] (II) fglrx(4): [uki] DRM interface version 1.0
[ 14.517] (II) fglrx(4): [uki] created "fglrx" driver at busid "PCI:1:0:0"
[ 14.517] (II) fglrx(4): [uki] added 8192 byte SAREA at 0x2000
[ 14.517] (II) fglrx(4): [uki] mapped SAREA 0x2000 to 0x7fb706a97000
[ 14.518] (II) fglrx(4): [uki] framebuffer handle = 0x3000
[ 14.518] (II) fglrx(4): [uki] added 1 reserved context for kernel
[ 14.518] (II) fglrx(4): swlDriScreenInit done
[ 14.518] (EE) fglrx(4): Not enough video memory to allocate primary surface (frame buffer).
[ 14.518] (II) fglrx(4): Shutdown CMMQS
[ 14.518] (II) fglrx(4): [uki] removed 1 reserved context for kernel
[ 14.518] (II) fglrx(4): [uki] unmapping 8192 bytes of SAREA 0x2000 at 0x7fb706a97000
[ 14.518] (WW) fglrx(4): ***********************************************************
[ 14.518] (WW) fglrx(4): * DRI initialization failed *
This line in particular drew my attention: fglrx(4): Not enough video memory to allocate primary surface (frame buffer). The card has two gigabytes of memory.
I'm using latest stable driver from AMD (12.8), built .debs with this guide: What is the correct way to install ATI Catalyst Video Drivers?
Somebody else that has had this error worked around it with the "nopat" kernel param; I tried that and it didn't help ( https://bugs.launchpad.net/ubuntu/+source/fglrx-installer/+bug/1004546 )
I also messed with ServerLayout in xorg.conf a bit, wondering if 9600 horizontal pixels was too much:
Section "ServerLayout"
Identifier "aticonfig Layout"
Screen 0 "aticonfig-Screen[0]-0" 0 0
Screen "amdcccle-Screen[1]-1" 1920 0
Screen "amdcccle-Screen[1]-2" 3840 0
Screen "amdcccle-Screen[1]-3" 5760 0
# my failure occurs with either of these lines:
Screen "amdcccle-Screen[1]-4" 5760 1200
# Screen "amdcccle-Screen[1]-4" 7680 0
EndSection
Update: 3840 Limit?
When I use the Ubuntu Displays configurator instead of AMD's thing, it seems to tell me that there's a hard limit of 3840x3840 for the entire virtual desktop:
requested position/size for CRTC 149 is outside the allowed limit: position=(3840,3840), size=(1920, 1200), maximum=(3840,3840)
Googling around, I see others encountering the same error with a variety of maximum limits - how is this number derived? How might I increase it?
As a workaround for now I can rearrange the screens on this dialog to fit inside the 3840x3840 square, but that doesn't reflect the physical layout of my displays.
I don't have enough rep yet on this stack exchange site to embed an image, but here's the dialog with the 3840 limit: http://i.stack.imgur.com/CKAld.png
