[PATCH 4/17] fbcon: Initialize new driver when old driver is released

["Antonino A. Daplas" <adaplas@gmail.com>]

If machine has more than 1 driver installed, and they all drive the same
hardware, it's possible that the driver's fb_release() method will attempt
to restore the hardware state to the initial state.  This will leave
the new driver in an undefined state.  To prevent this problem, initialize
the new driver by calling fb_set_par() when the old driver is released by
fbcon.

Signed-off-by: Antonino Daplas<adaplas@pol.net>
---
 fbcon.c |    9 +++++++++
 1 files changed, 9 insertions(+)


diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -630,6 +630,15 @@ static int con2fb_release_oldinfo(struct
 		kfree(oldinfo->fbcon_par);
 		oldinfo->fbcon_par = NULL;
 		module_put(oldinfo->fbops->owner);
+		/*
+		  If oldinfo and newinfo are driving the same hardware,
+		  the fb_release() method of oldinfo may attempt to
+		  restore the hardware state.  This will leave the
+		  newinfo in an undefined state. Thus, a call to
+		  fb_set_par() may be needed for the newinfo.
+		*/
+		if (newinfo->fbops->fb_set_par)
+			newinfo->fbops->fb_set_par(newinfo);
 	}
 
 	return err;




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