Multimonitor support on ARM

I don't know if this is fixable or even considered for ARM.
I have a Lilliput 7" USB LCD that works fine on a Beaglebone White with the udlfb kernel module.

I started looking at the issue after a guy asked me if it also works on the ODROID.
For Software Defined Radio (SDR) which is of prime interest it would be nice to have a portable/mobile SDR with a small keyboard/7" USB LCD or touchscreen, all as a compact unit.

Digging further. The Beaglebone does not have a GPU so that's probably why it works there and on x86_64 as it's dependent on x86. The ODROID has a Mali400 GPU.

In /etc/modprobe.d/blacklist-framebuffer.conf
##blacklist udlfb
blacklist udl

The Lilliput came up on the ODROID with a green screen background but no display.

root@odroid:~# grep -i arbiter /var/log/Xorg.0.log.old
[   200.165] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support

In kernels on x86_64 there is an option that is not available for ARM. # CONFIG_VGA_ARB is not set

The files are present in the kernel but no config option, configuring it by hand and doing "make oldconfig" removes it as it depends on PCI and x86.

root@odroid:/b1/linux-3.8.13.23# ls drivers/gpu/vga
built-in.o  Kconfig  Makefile  modules.builtin  modules.order vgaarb.c  vga_switcheroo.c

drivers/gpu/vga/Kconfig
===============
config VGA_ARB
bool "VGA Arbitration" if EXPERT
default y
depends on (PCI && !S390)
help
Some "legacy" VGA devices implemented on PCI typically have
the same
hard-decoded addresses as they did on ISA. When multiple PCI
devices
are accessed at same time they need some kind of
coordination. Please
see Documentation/vgaarbiter.txt for more details. Select
this to
enable VGA arbiter.

config VGA_ARB_MAX_GPUS
int "Maximum number of GPUs"
default 16
depends on VGA_ARB
help
Reserves space in the kernel to maintain resource locking for multiple GPUS. The overhead for each GPU is very small.

config VGA_SWITCHEROO
bool "Laptop Hybrid Graphics - GPU switching support" depends on X86
depends on ACPI
select VGA_ARB
help
Many laptops released in 2008/9/10 have two GPUs with a
multiplexer
to switch between them. This adds support for dynamic
switching when
X isn't running and delayed switching until the next logoff.
This
feature is called hybrid graphics, ATI PowerXpress, and Nvidia HybridPower.

Regards
Sid.

Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
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Microsoft Windows Free Zone - Linux used for all Computing Tasks