The changes in commit 20743e8 removed the s_max_virtual_consoles
constant and hardcoded the number of consoles to 4. But in
PS2KeyboardDevice the keyboard shortcuts for switching to consoles were
hardcoded to 6.
I reintroduced the constant and added it in both places.
If we tried to change the resolution before of this patch, we triggered
a kernel crash due to mmaping the framebuffer device again.
Therefore, on mmaping of the framebuffer device, we create an entire new
set of VMObjects and Regions for the new settings.
Then, when we change the resolution, the framebuffersconsole needs to be
updated with the new resolution and also to be refreshed with the new
settings. To ensure we handle both shrinking of the resolution and
growth of it, we only copy the right amount of available data from the
cells Region.
As we removed the support of VBE modesetting that was done by GRUB early
on boot, we need to determine if we can modeset the resolution with our
drivers, and if not, we should enable text mode and ensure that
SystemServer knows about it too.
Also, SystemServer should first check if there's a framebuffer device
node, which is an indication that text mode was not even if it was
requested. Then, if it doesn't find it, it should check what boot_mode
argument the user specified (in case it's self-test). This way if we
try to use bochs-display device (which is not VGA compatible) and
request a text mode, it will not honor the request and will continue
with graphical mode.
Also try to print critical messages with mininum memory allocations
possible.
In LibVT, We make the implementation flexible for kernel-specific
methods that are implemented in ConsoleImpl class.
