[Intel-gfx] [PATCH i-g-t] lib/sysfs: Fix fbcon rebind

[Chris Wilson]

Quoting ville.syrjala at linux.intel.com (2017-09-06 14:04:01)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> "echo 1 > vtconN/bind" doesn't actually do anything. Looks like the only
> way to rebind fbcon is to unbind the current console.
> 
> I suppose the failure to rebind might be a kernel bug, but I can't be
> bothered to decode the vt.c spaghetti so let's just try to handle this
> in igt. For simplicity let's assume the currently bound console is the
> dummy console and unbind that when we want to rebind fbcon. That works
> for me.
> 
> With rebinding not working we can't really tell wich console is going
> to get bound anyway, so there's no way to make this code really robust,
> assuming we ever had more than these two console drivers involved.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Ok, if it works in one direction, it should work in the other... And
pragmatically if it works, it works. However, I do worry if that if we
have been measuring our test runtimes with never having to rebind fbcon
if we suddenly get a slowdown...

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris