Hello Florian,
This patch allows having multiple visible consoles that receive
display updates. For example one can have running "top" to monitor
the system on fb0 and at the same time work on a shell on fb1.
I hate to report this, because I would really appreciate this feature,
but your patch (applied against kernel 3.0) breaks my machine.
I have an x86-64 machine with a dual-GPU ATI Radeon HD 4850 X2 (which
acts essentially as two discrete R700s) driven by the "radeon" KMS driver.
If I use the "fbcon=map:01" boot option to map the even-numbered VCs to
the first GPU and the odd-numbered VCs to the second GPU, the kernel
patched with your patch encounters some sort of soft-lockup when
initializing the second GPU (i.e. creating the fb1) while booting. The
is no panic or oops message and I can reset the machine by hitting
ctrl+alt+del, but there is no further progress. I can provide further
observations if you would like to.
Best regards
Martin Decky