Lenovo R60 screen corrupt immediately after install

Version : Ubuntu 18.04.1 LTS

Immediately after the install completes. The computer restarts to a corrupt login screen.

Hardware : Lenovo R60
Video : 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV515/M54 [Mobility Radeon X1400]

Xorg.log

        AMD Radeon HD 6900M Series, Mobility Radeon HD 6000 Series, BARTS,
        AMD Radeon HD 6800 Series, AMD Radeon HD 6700 Series, TURKS, CAICOS,
        ARUBA, TAHITI, PITCAIRN, VERDE, OLAND, HAINAN, BONAIRE, KABINI,
        MULLINS, KAVERI, HAWAII
[ 13.133] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[ 13.133] (II) FBDEV: driver for framebuffer: fbdev
[ 13.133] (II) VESA: driver for VESA chipsets: vesa
[ 13.135] (II) [KMS] drm report modesetting isn't supported.
[ 13.135] (EE) open /dev/dri/card0: No such file or directory
[ 13.135] (WW) Falling back to old probe method for modesetting
[ 13.135] (EE) open /dev/dri/card0: No such file or directory
[ 13.135] (II) Loading sub module "fbdevhw"
[ 13.135] (II) LoadModule: "fbdevhw"
[ 13.136] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 13.137] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 13.137] compiled for 1.19.6, module version = 0.0.2
[ 13.137] ABI class: X.Org Video Driver, version 23.0
[ 13.137] (**) FBDEV(2): claimed PCI slot 1@0:0:0
[ 13.137] (II) FBDEV(2): using default device
[ 13.137] (WW) Falling back to old probe method for vesa
[ 13.137] (EE) Screen 0 deleted because of no matching config section.
[ 13.137] (II) UnloadModule: "radeon"
[ 13.137] (EE) Screen 0 deleted because of no matching config section.
[ 13.137] (II) UnloadModule: "modesetting"
[ 13.138] (II) FBDEV(0): Creating default Display subsection in Screen section
        "Default Screen Section" for depth/fbbpp 24/32
[ 13.138] (==) FBDEV(0): Depth 24, (==) framebuffer bpp 32

After some digging, on another computer, adding nomodeset to the kernal startup parameters helps. Edited /etc/default/grub

GRUB_CMDLINE_LINUX="nomodeset"

$update-grub
provides a usable but degraded session.

The screen resolution is 1400x1050.