How to force Xorg to 800x480px ?

[awatar100]

Hello,
I'm  to force Xorg to change  800x480px (small 5inch thing from RBpi).
Its hookup to old thin client that have VIA chip (Hardware: CLE266 chipset with VT8623 intergarted graphics, VIA C3 processor Samuel 2)
can somone be so polite and give me hint what to do ?
Xvesa -listmodes don't show this configuration so ... is there are some drivers for it or  there is "just" magical command to force it to work.
Ps old info that i see in google is about Intel chip and "915resolution.tcz" but it dont see Intel HW ;/

[curaga]

Xvesa can only use the VESA modes that are available. To use custom modes, you need to use Xorg and a driver for your GPU (unichrome or openchrome).

[CNK]

If you can install a Linux kernel framebuffer driver (porobably vt8623fb, but I'm not sure what the easiest way is to install that in Tiny Core) for your GPU which supports that resolution, you may also be able to use Xfbdev, which may boot faster than full Xorg.

[adb014]

My prefered way to change the default resolution is to do this

cat << EOF > /usr/local/share/X11/xorg.conf.d/11-tinycore.conf
Section "Monitor"
  Identifier "TinyCore"
  Option "PreferredMode" "1600x900"
EndSection

Section "Screen"
  Identifier "Screen0"
  Monitor "TinyCore"
  SubSection "Display"
    Depth 24
    Modes "1600x900" "1024x768" "800x600"
  EndSubSection
EndSection
EOF
cat << EOF >> /opt/.filetool.lst
usr/local/share/X11/xorg.conf.d
EOF

D.