xen pvfb: Dynamic mode support (screen resizing)

The pvfb backend indicates dynamic mode support by creating node
feature_resize with a non-zero value in its xenstore directory.
xen-fbfront sends a resize notification event on mode change.  Fully
backwards compatible both ways.

Framebuffer size and initial resolution can be controlled through
kernel parameter xen_fbfront.video.  The backend enforces a separate
size limit, which it advertises in node videoram in its xenstore
directory.

xen-kbdfront gets the maximum screen resolution from nodes width and
height in the backend's xenstore directory instead of hardcoding it.

Additional goodie: support for larger framebuffers (512M on a 64-bit
system with 4K pages).

Changing the number of bits per pixels dynamically is not supported,
yet.

Ported from
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/92f7b3144f41
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/bfc040135633

Signed-off-by: Pat Campbell <plc@novell.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
index eaf69cf5b444..9ce3b3baf3a2 100644
--- a/drivers/input/xen-kbdfront.c
+++ b/drivers/input/xen-kbdfront.c
@@ -300,6 +300,16 @@ InitWait:
                  */
                 if (dev->state != XenbusStateConnected)
                         goto InitWait; /* no InitWait seen yet, fudge it */
+
+                /* Set input abs params to match backend screen res */
+                if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+                                 "width", "%d", &val) > 0)
+                        input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
+
+                if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+                                 "height", "%d", &val) > 0)
+                        input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
+
                 break;
 
         case XenbusStateClosing: