PM/gxfb: add hook to PM console layer that allows disabling of suspend VT switch

Prior to suspend, we allocate and switch to a new VT; after suspend, we switch
back to the original VT.  This can be slow, and is completely unnecessary if
the framebuffer we're using can restore video properly.

This adds a hook that allows drivers to select whether or not to do this vt
switch, and changes the gxfb driver to call this hook.  It also adds a module
param to gxfb to allow controlling of the vt switch (defaulting to no switch).

(Note: I'm not convinced that console_sem is the best way to protect this, but
we should probably have some form of locking..)

[akpm@linux-foundation.org: build fix]
Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/Documentation/fb/gxfb.txt b/Documentation/fb/gxfb.txt
index b56096142017..2f640903bbb2 100644
--- a/Documentation/fb/gxfb.txt
+++ b/Documentation/fb/gxfb.txt
@@ -45,7 +45,8 @@ Accepted options:
 mode_option     - specify the video mode.  Of the form
                   <x>x<y>[-<bpp>][@<refresh>]
 vram            - size of video ram (normally auto-detected)
-
+vt_switch       - enable vt switching during suspend/resume.  The vt
+                  switch is slow, but harmless.
 
 --
 Andres Salomon <dilinger@debian.org>