Ok, ora mi si è aperta, ho provato, ma c'è qualcosa che non va...

Ora connettere lo schermo esterno e lanciare di nuovo il comando xrandr:
(...)
Qui si può vedere che è ora connesso anche uno schermo DVI che supporta risoluzioni da 720x400 a 1024x768 con dati livelli di refresh.
Già, solo che facendolo a me non viene fuori niente di diverso... ecco ciò che appare, senza menzione alcuna dell'altro display:

codice:
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 2560 x 800
default connected 1280x800+0+0 0mm x 0mm
   2560x800       60.0
   1280x800       60.0*
   1280x768       60.0
   800x600        85.0     75.0     72.0     70.0     60.0     56.0    160.0    120.0    100.0     90.0
   1024x768       60.0     85.0     75.0     72.0     70.0    120.0    100.0     90.0
   1024x480       60.0
   848x480        60.0
   720x576        60.0
   720x480        60.0
   640x480        85.0     75.0     72.0     60.0    160.0    120.0    100.0     90.0
   640x400        75.0     60.0
   640x350        60.0
   512x384        60.0
   400x300        75.0     60.0
   320x240        75.0     60.0
   320x200        75.0     60.0
Se gli do
xrandr --output VGA (provato anche VGA-0 e VGA-1) --mode 1280x960 --rate 85
si limita a eseguire il comando, ma non cambia nulla.

Se provo così:
xrandr --output default --mode 1280x960 --rate 85
mi dice "xrandr: cannot find mode 1280x960".

Riesco a cambiare qualcosa solo così:
xrandr --output default --mode 1024x768 --rate 85

Così il CRT diventa finalmente utilizzabile, ma cambia a 1024x768 anche la risoluzione del display LCD. E se chiudo il display del portatile... si spegne anche il CRT :| e in ogni caso 1024x768 è poco per un 21"...
Insomma non posso trattarli separatamente, e non posso dargli la risoluzione che voglio.

Che faccio adesso? :/

Edit: se può servire, ecco il mio xorg.conf:

codice:
Section "ServerLayout"
	Identifier     "Default Layout"
	Screen      0  "Default Screen" 0 0
	Screen         "screen1" RightOf "Default Screen"
	InputDevice    "Synaptics Touchpad"
EndSection

Section "Files"
EndSection

Section "Module"
	Load  "GLcore"
	Load  "glx"
	Load  "dbe"
	Load  "v4l"
EndSection

Section "InputDevice"
	Identifier  "Generic Keyboard"
	Driver      "kbd"
	Option	    "XkbRules" "xorg"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "it"
EndSection

Section "InputDevice"
	Identifier  "Configured Mouse"
	Driver      "mouse"
	Option	    "CorePointer"
EndSection

Section "InputDevice"
	Identifier  "Synaptics Touchpad"
	Driver      "synaptics"
	Option	    "SendCoreEvents" "true"
	Option	    "Device" "/dev/psaux"
	Option	    "Protocol" "auto-dev"
	Option	    "HorizEdgeScroll" "0"
EndSection

Section "Monitor"
	Identifier   "Configured Monitor"
	VendorName   "Generic LCD Display"
	ModelName    "LCD Panel 1280x800"
	HorizSync    31.5 - 50.0
	VertRefresh  56.0 - 65.0
	Gamma        1
	ModeLine     "800x600@56" 36.0 800 824 896 1024 600 601 603 625 +hsync +vsync
	ModeLine     "800x600@60" 40.0 800 840 968 1056 600 601 605 628 +hsync +vsync
	ModeLine     "1280x768@60" 80.1 1280 1344 1480 1680 768 769 772 795 -hsync +vsync
	ModeLine     "1280x720@60" 74.5 1280 1336 1472 1664 720 721 724 746 -hsync +vsync
	ModeLine     "1280x800@60" 83.5 1280 1344 1480 1680 800 801 804 828 -hsync +vsync
EndSection

Section "Monitor"

 #   
	Identifier   "monitor1"
	VendorName   "Belinea"
	ModelName    "Belinea 10 80 30 / Art. No. 122101"
	HorizSync    30.0 - 125.0
	VertRefresh  50.0 - 160.0
	Gamma        1
	ModeLine     "640x480@60" 25.2 640 656 752 800 480 490 492 525 -hsync -vsync
	ModeLine     "640x480@72" 31.5 640 664 704 832 480 489 491 520 -hsync -vsync
	ModeLine     "640x480@75" 31.5 640 656 720 840 480 481 484 500 -hsync -vsync
	ModeLine     "640x480@85" 36.0 640 696 752 832 480 481 484 509 -hsync -vsync
	ModeLine     "800x600@56" 36.0 800 824 896 1024 600 601 603 625 +hsync +vsync
	ModeLine     "800x600@72" 50.0 800 856 976 1040 600 637 643 666 +hsync +vsync
	ModeLine     "800x600@75" 49.5 800 816 896 1056 600 601 604 625 +hsync +vsync
	ModeLine     "800x600@85" 56.3 800 832 896 1048 600 601 604 631 +hsync +vsync
	ModeLine     "800x600@60" 40.0 800 840 968 1056 600 601 605 628 +hsync +vsync
	ModeLine     "832x624@75" 57.3 832 864 928 1152 624 625 628 667 -hsync -vsync
	ModeLine     "1024x768@85" 94.5 1024 1072 1168 1376 768 769 772 808 +hsync +vsync
	ModeLine     "1024x768@75" 78.8 1024 1040 1136 1312 768 769 772 800 +hsync +vsync
	ModeLine     "1024x768@70" 75.0 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
	ModeLine     "1024x768@60" 65.0 1024 1048 1184 1344 768 771 777 806 -hsync -vsync
	ModeLine     "1024x768@43" 44.9 1024 1032 1208 1264 768 768 776 817 +hsync +vsync interlace
	ModeLine     "1152x864@75" 108.0 1152 1216 1344 1600 864 865 868 900 +hsync +vsync
	ModeLine     "1280x1024@75" 135.0 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync
	ModeLine     "1280x960@60" 102.1 1280 1360 1496 1712 960 961 964 994 -hsync +vsync
	ModeLine     "1280x960@85" 148.5 1280 1344 1504 1728 960 961 964 1011 +hsync +vsync
	ModeLine     "1280x1024@85" 157.5 1280 1344 1504 1728 1024 1025 1028 1072 +hsync +vsync
	ModeLine     "1280x1024@60" 108.0 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync
	ModeLine     "1280x960@75" 129.9 1280 1368 1504 1728 960 961 964 1002 -hsync +vsync
	ModeLine     "1400x1050@60" 122.6 1400 1488 1640 1880 1050 1051 1054 1087 -hsync +vsync
	ModeLine     "1400x1050@75" 155.8 1400 1496 1648 1896 1050 1051 1054 1096 -hsync +vsync
	ModeLine     "1600x1200@65" 175.5 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync
	ModeLine     "1600x1200@60" 162.0 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync
	ModeLine     "1600x1200@75" 202.5 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync
	ModeLine     "1600x1200@70" 189.0 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync
	ModeLine     "1600x1200@85" 229.5 1600 1664 1856 2160 1200 1201 1204 1250 +hsync +vsync
	ModeLine     "1792x1344@75" 261.0 1792 1888 2104 2456 1344 1345 1348 1417 -hsync +vsync
	ModeLine     "1792x1344@60" 204.8 1792 1920 2120 2448 1344 1345 1348 1394 -hsync +vsync
	ModeLine     "1856x1392@60" 218.3 1856 1952 2176 2528 1392 1393 1396 1439 -hsync +vsync
	ModeLine     "1856x1392@75" 288.0 1856 1984 2208 2560 1392 1393 1396 1500 -hsync +vsync
	ModeLine     "1920x1440@60" 234.0 1920 2048 2256 2600 1440 1441 1444 1500 -hsync +vsync
	ModeLine     "1920x1440@75" 297.0 1920 2064 2288 2640 1440 1441 1444 1500 -hsync +vsync
	ModeLine     "2048x1536@60" 266.9 2048 2200 2424 2800 1536 1537 1540 1589 -hsync +vsync
	ModeLine     "2048x1536@75" 340.5 2048 2216 2440 2832 1536 1537 1540 1603 -hsync +vsync
EndSection

Section "Device"
	Identifier  "Configured Video Device"
	Driver      "fglrx"
	BoardName   "fglrx"
	BusID       "PCI:1:0:0"
EndSection

Section "Device"

 #   
	Identifier  "device1"
	Driver      "fglrx"
	BoardName   "fglrx"
	BusID       "PCI:1:0:0"
	Screen      1
EndSection

Section "Screen"
	Identifier "Default Screen"
	Device     "Configured Video Device"
	Monitor    "Configured Monitor"
	DefaultDepth     24
	SubSection "Display"
		Virtual   1280 800
		Depth     24
		Modes    "1280x800@60" "1280x720@60" "1280x768@60" "800x600@60" "800x600@56"
	EndSubSection
EndSection

Section "Screen"

 #   
	Identifier "screen1"
	Device     "device1"
	Monitor    "monitor1"
	DefaultDepth     24
	SubSection "Display"
		Depth     24
		Modes    "800x600@60" "832x624@75" "800x600@85" "1024x768@85" "800x600@75" "1024x768@75" "800x600@72" "1024x768@70" "800x600@56" "1024x768@60" "640x480@85" "1024x768@43" "640x480@75" "1152x864@75" "640x480@72" "1280x1024@75" "640x480@60" "1280x960@60" "1280x960@85" "1280x1024@85" "1280x1024@60" "1280x960@75" "1400x1050@60" "1400x1050@75" "1600x1200@65" "1600x1200@60" "1600x1200@75" "1600x1200@70" "1600x1200@85" "1792x1344@75" "1792x1344@60" "1856x1392@60" "1856x1392@75" "1920x1440@60" "1920x1440@75" "2048x1536@60" "2048x1536@75"
	EndSubSection
EndSection
Il monitor Belinea 10 80 30 è il CRT che sto cercando di far funzionare...