Xinerama cria uma viewport de pan

Question

EDIT: I've created a bug report: https://bugs.freedesktop.org/show_bug.cgi?id=48458

Minha configuração

Eu tenho 4 monitores, 1920x1080, que estão no modo retrato (girado à esquerda). Eles estão conectados a duas placas gráficas radeon.

Como de costume, uma foto diz mais que mil palavras.

Oproblema

TudofuncionabemquandooXineramaestádesativado.MasquandoeuhabilitooXinerama,ascoisasficamestranhas.Quandoeumovoomousedatelaeretorno,oconteúdodatelacomeçaasemovercomomouse,somentenestemonitor.Parecequeotamanhodatelavirtualnãocorrespondeaotamanhorealdatela,oqueativaumaviewportdepan.Algumaideiadecomopararisso?

Ovídeo

Eucrieiumvídeoparademonstraroproblema: link

xorg.conf

Este é o meu xorg.conf :

Section "ServerLayout"
 ##################[ Evilness begins here ]#############
 Option "Xinerama" "on"       # <--- Makes it go b0rked!
 ##################[    End of all evil   ]#############

 Identifier     "BOFH Console of Doom"
 Screen         0 "Screen-0" 0 0
 Screen         1 "Screen-1" RightOf "Screen-0"
 Screen         2 "Screen-2" RightOf "Screen-1"
 Screen         3 "Screen-3" RightOf "Screen-2"
EndSection

Section "ServerFlags"
  Option "RandR" "false"
EndSection


Section "Module"
  Load  "dbe"
  Load  "dri"
  Load  "extmod"
  Load  "dri2"
  Load  "record"
  Load  "glx"
EndSection

Section "Monitor"
 Identifier   "Monitor-0"
 Option      "Rotate" "left"
EndSection

Section "Monitor"
 Identifier   "Monitor-1"
 Option      "Rotate" "left"
EndSection

Section "Monitor"
 Identifier   "Monitor-2"
 Option      "Rotate" "left"
EndSection

Section "Monitor"
 Identifier   "Monitor-3"
 Option      "Rotate" "left"
EndSection

Section "Device"
 Identifier  "Radeon-0-0"
 Driver      "radeon"
 BusID       "PCI:9:0:0"
 Option      "ZaphodHeads" "DVI-0"
 Screen      0
EndSection

Section "Device"
 Identifier  "Radeon-0-1"
 Driver      "radeon"
 BusID       "PCI:9:0:0"
 Option      "ZaphodHeads" "DVI-1"
 Screen      1
EndSection

Section "Device"
 Identifier  "Radeon-1-0"
 Driver      "radeon"
 BusID       "PCI:4:0:0"
 Option      "ZaphodHeads" "DVI-2"
 Screen      0
EndSection

Section "Device"
 Identifier  "Radeon-1-1"
 Driver      "radeon"
 BusID       "PCI:4:0:0"
 Option      "ZaphodHeads" "DVI-3"
 Screen      1
EndSection

Section "Screen"
 Identifier "Screen-0"
 Device     "Radeon-0-0"
 Monitor    "Monitor-0"
 DefaultDepth     24
 SubSection "Display"
  Viewport   0 0
  Depth     24
 EndSubSection
EndSection

Section "Screen"
 Identifier "Screen-1"
 Device     "Radeon-0-1"
 Monitor    "Monitor-1"
 DefaultDepth     24
 SubSection "Display"
  Viewport   0 0
  Depth     24
 EndSubSection
EndSection

Section "Screen"
 Identifier "Screen-2"
 Device     "Radeon-1-0"
 Monitor    "Monitor-2"
 DefaultDepth     24
 SubSection "Display"
  Viewport   0 0
  Depth     24
 EndSubSection
EndSection

Section "Screen"
 Identifier "Screen-3"
 Device     "Radeon-1-1"
 Monitor    "Monitor-3"
 DefaultDepth     24
 SubSection "Display"
  Viewport   0 0
  Depth     24
 EndSubSection
EndSection