I'm sorry for the long time for previous message. The laptop model is Sony vgn-sz1m, now about 3 years old. To attempt a work-around I added explicitly the modeline for 1440x900, using those parameters: Modeline "1440x900" 103.97 1440 1496 1624 1856 900 900 902 933 the results is not very good: the desktop seems to be few percents wider than the panel. The randr --verbos output now appears as follow: Screen 0: minimum 320 x 200, current 1280 x 800, maximum 1680 x 1200 VGA connected (normal left inverted right x axis y axis) Identifier: 0x3b Timestamp: 22520 Subpixel: unknown Clones: CRTCs: 0 1 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: 1440x900 (0xf8) 104.0MHz h: width 1440 start 1496 end 1624 total 1856 skew 0 clock 56.0KHz v: height 900 start 900 end 902 total 933 clock 60.0Hz 1360x768 (0xf9) 84.8MHz -HSync +VSync h: width 1360 start 1432 end 1568 total 1776 skew 0 clock 47.7KHz v: height 768 start 771 end 781 total 798 clock 59.8Hz 1152x864 (0xfa) 81.6MHz -HSync +VSync h: width 1152 start 1216 end 1336 total 1520 skew 0 clock 53.7KHz v: height 864 start 865 end 868 total 895 clock 60.0Hz 1024x768 (0x42) 65.0MHz -HSync -VSync h: width 1024 start 1048 end 1184 total 1344 skew 0 clock 48.4KHz v: height 768 start 771 end 777 total 806 clock 60.0Hz 800x600 (0x47) 40.0MHz +HSync +VSync h: width 800 start 840 end 968 total 1056 skew 0 clock 37.9KHz v: height 600 start 601 end 605 total 628 clock 60.3Hz 640x480 (0x4c) 25.2MHz -HSync -VSync h: width 640 start 656 end 752 total 800 skew 0 clock 31.5KHz v: height 480 start 490 end 492 total 525 clock 59.9Hz LVDS connected 1280x800+0+0 (0x3e) normal (normal left inverted right x axis y axis) 0mm x 0mm Identifier: 0x3c Timestamp: 22520 Subpixel: horizontal rgb Clones: CRTC: 1 CRTCs: 1 Panning: 0x0+0+0 Tracking: 0x0+0+0 Border: 0/0/0/0 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: PANEL_FITTING: full_aspect supported: center full_aspect full BACKLIGHT_CONTROL: kernel supported: native legacy combination kernel BACKLIGHT: 7 (0x00000007) range: (0,7) 1280x800 (0x3e) 83.5MHz *current +preferred h: width 1280 start 1352 end 1480 total 1680 skew 0 clock 49.7KHz v: height 800 start 803 end 809 total 831 clock 59.8Hz 1024x768 (0x3f) 94.5MHz +HSync +VSync h: width 1024 start 1072 end 1168 total 1376 skew 0 clock 68.7KHz v: height 768 start 769 end 772 total 808 clock 85.0Hz 1024x768 (0x40) 78.8MHz +HSync +VSync h: width 1024 start 1040 end 1136 total 1312 skew 0 clock 60.0KHz v: height 768 start 769 end 772 total 800 clock 75.0Hz 1024x768 (0x41) 75.0MHz -HSync -VSync h: width 1024 start 1048 end 1184 total 1328 skew 0 clock 56.5KHz v: height 768 start 771 end 777 total 806 clock 70.1Hz 1024x768 (0x42) 65.0MHz -HSync -VSync h: width 1024 start 1048 end 1184 total 1344 skew 0 clock 48.4KHz v: height 768 start 771 end 777 total 806 clock 60.0Hz 832x624 (0x43) 57.3MHz -HSync -VSync h: width 832 start 864 end 928 total 1152 skew 0 clock 49.7KHz v: height 624 start 625 end 628 total 667 clock 74.6Hz 800x600 (0x44) 56.3MHz +HSync +VSync h: width 800 start 832 end 896 total 1048 skew 0 clock 53.7KHz v: height 600 start 601 end 604 total 631 clock 85.1Hz 800x600 (0x45) 50.0MHz +HSync +VSync h: width 800 start 856 end 976 total 1040 skew 0 clock 48.1KHz v: height 600 start 637 end 643 total 666 clock 72.2Hz 800x600 (0x46) 49.5MHz +HSync +VSync h: width 800 start 816 end 896 total 1056 skew 0 clock 46.9KHz v: height 600 start 601 end 604 total 625 clock 75.0Hz 800x600 (0x47) 40.0MHz +HSync +VSync h: width 800 start 840 end 968 total 1056 skew 0 clock 37.9KHz v: height 600 start 601 end 605 total 628 clock 60.3Hz 800x600 (0x48) 36.0MHz +HSync +VSync h: width 800 start 824 end 896 total 1024 skew 0 clock 35.2KHz v: height 600 start 601 end 603 total 625 clock 56.2Hz 640x480 (0x49) 36.0MHz -HSync -VSync h: width 640 start 696 end 752 total 832 skew 0 clock 43.3KHz v: height 480 start 481 end 484 total 509 clock 85.0Hz 640x480 (0x4a) 31.5MHz -HSync -VSync h: width 640 start 664 end 704 total 832 skew 0 clock 37.9KHz v: height 480 start 489 end 492 total 520 clock 72.8Hz 640x480 (0x4b) 31.5MHz -HSync -VSync h: width 640 start 656 end 720 total 840 skew 0 clock 37.5KHz v: height 480 start 481 end 484 total 500 clock 75.0Hz 640x480 (0x4c) 25.2MHz -HSync -VSync h: width 640 start 656 end 752 total 800 skew 0 clock 31.5KHz v: height 480 start 490 end 492 total 525 clock 59.9Hz 720x400 (0x4d) 35.5MHz -HSync +VSync h: width 720 start 756 end 828 total 936 skew 0 clock 37.9KHz v: height 400 start 401 end 404 total 446 clock 85.0Hz 640x400 (0x4e) 31.5MHz -HSync +VSync h: width 640 start 672 end 736 total 832 skew 0 clock 37.9KHz v: height 400 start 401 end 404 total 445 clock 85.1Hz 640x350 (0x4f) 31.5MHz +HSync -VSync h: width 640 start 672 end 736 total 832 skew 0 clock 37.9KHz v: height 350 start 382 end 385 total 445 clock 85.1Hz TV disconnected (normal left inverted right x axis y axis) Identifier: 0x3d Timestamp: 22520 Subpixel: unknown Clones: CRTCs: 0 1 Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 filter: BOTTOM: 37 (0x00000025) range: (0,100) RIGHT: 46 (0x0000002e) range: (0,100) TOP: 36 (0x00000024) range: (0,100) LEFT: 54 (0x00000036) range: (0,100) TV_FORMAT: NTSC-M supported: NTSC-M NTSC-443 NTSC-J PAL-M PAL-N PAL