TvE 2100

At 2100 feet above Santa Barbara

Getting 1680x1050 With a via Graphics Chip

I have a VIA mini-ITX board with a fan-less VIA Eden processor. Really nice and quiet! But trouble came whan I bought a nice Dell 2007WFP display for it which has a native resolution of 1680 by 1050 and I tried to get Ubuntu to run at that resolution. The problem is that the driver does not have the information to run at 1680x1050 and that the CLE266 graphics device is limited to 150Mhz pixel clock. To make a way too long story short, the trick is to add the following mode line to /etc/X11/xorg.conf:

Modeline "1680x1050a" 148.5 1680 1784 1960 2240 1050 1053 1059 1089

Note that the pixel clock at 148.hMhz is just below the limit of the hardware, but not only that, it also has to be exactly one of a few dozen values that are in a table in the driver (look in via_mode.h). So the way I arrived at this modeline is to choose the highest pixel clock under 150Mhz and to choose the values provided by the display via DDC in /var/log/Xor.0.log:

(II) VIA(0): Supported additional Video Mode:
(II) VIA(0): clock: 146.2 MHz   Image Size:  434 x 270 mm
(II) VIA(0): h_active: 1680  h_sync: 1784  h_sync_end 1960 h_blank_end 2240 h_border: 0
(II) VIA(0): v_active: 1050  v_sync: 1053  v_sync_end 1059 v_blanking: 1089 v_border: 0