Ubuntu bug is: https://launchpad.net/bugs/380009

Hardware: HP Compaq nc8430, ATI Technologies Inc M56P [Radeon Mobility X1600]

I am experiencing huge font sizes in GDM, probably for the same reason as in Bug #353074. Here is the relevant part of Xorg.log, please note the line which says "Image Size: 289 x 21 mm":

(II) RADEON(0): EDID vendor "LPL", prod id 5750
(II) RADEON(0): Printing DDC gathered Modelines:
(II) RADEON(0): Modeline "1280x800"x0.0 71.25 1280 1328 1360 1440 800 802 808 823 -hsync -vsync (49.5 kHz)
(II) RADEON(0): Output: LVDS, Detected Monitor Type: 2
(II) RADEON(0): EDID data from the display on output: LVDS ----------------------
(II) RADEON(0): Manufacturer: LPL Model: 1676 Serial#: 0
(II) RADEON(0): Year: 2005 Week: 0
(II) RADEON(0): EDID Version: 1.2
(II) RADEON(0): Digital Display Input
(II) RADEON(0): Max Image Size [cm]: horiz.: 33 vert.: 21
(II) RADEON(0): Gamma: 2.20
(II) RADEON(0): No DPMS capabilities specified
(II) RADEON(0): Supported color encodings: RGB 4:4:4 YCrCb 4:4:4
(II) RADEON(0): First detailed timing is preferred mode
(II) RADEON(0): redX: 0.590 redY: 0.344 greenX: 0.323 greenY: 0.534
(II) RADEON(0): blueX: 0.156 blueY: 0.138 whiteX: 0.312 whiteY: 0.328
(II) RADEON(0): Manufacturer's mask: 0
(II) RADEON(0): Supported additional Video Mode:
(II) RADEON(0): clock: 71.2 MHz Image Size: 289 x 21 mm
(II) RADEON(0): h_active: 1280 h_sync: 1328 h_sync_end 1360 h_blank_end 1440 h_border: 0
(II) RADEON(0): v_active: 800 v_sync: 802 v_sync_end 808 v_blanking: 823 v_border: 0
(WW) RADEON(0): Unknown vendor-specific block 0
(II) RADEON(0): LGPhilipsLCD
(II) RADEON(0): LP154W01-TLA8
(II) RADEON(0): EDID (in hex):
(II) RADEON(0): 00ffffffffffff00320c761600000000
(II) RADEON(0): 000f0102802115780a0f109758528828
(II) RADEON(0): 23505400000001010101010101010101
(II) RADEON(0): 010101010101d51b00a0502017303020
(II) RADEON(0): 26002115100000190000000000000000
(II) RADEON(0): 00000000000000000000000000fe004c
(II) RADEON(0): 475068696c6970734c43440a000000fe
(II) RADEON(0): 004c503135345730312d544c41380076

Note that the detailed mode reports as  289 x 21 mm.  The vertical size is clearly mis-reported in cm rather than mm.