The added line didn't work for me. Here's what did (from: https://wiki.ubuntu.com/HardwareSupportComponentsVideoCardsPoulsboAlternatives)...
Getting 1366x768 resolution
Create file /etc/grub.d/01_915resolution with lines
echo insmod 915resolution
echo 915resolution 58 1366 768 32
chmod +x /etc/grub.d/01_915resolution
In file /etc/default/grub, assign value 1366x768x32 to variables GRUB_GFXMODE and GRUB_GFXPAYLOAD_LINUX:
reboot, now you have 1366x768 resolution.
I already had that resolution, but with the added commands above I can now see the screen too.