[vram] Add "vram" built-in setting to dump video RAM

The "vram" setting returns the (Base64-encoded) contents of video RAM,
and can be used to capture a screenshot.  For example: after running
memtest.0 and encountering an error, the output can be captured and
sent to a remote server for later diagnosis:

  #!ipxe
  chain -a http://server/memtest.0 && goto ok || goto bad
  :bad
  params
  param errno ${errno}
  param vram ${vram}
  chain -a http://server/report.php##params
  :ok

Inspired-by: Christian Nilsson <nikize@gmail.com>
Originally-implemented-by: Christian Nilsson <nikize@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

0 files changed, 0 insertions, 0 deletions