We must cache these states so we will never draw to the framebuffer while
it is suspended or blanked.

Signed-off-by: David Herrmann <dh.herrm...@googlemail.com>
---
 drivers/video/console/fblog.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/video/console/fblog.c b/drivers/video/console/fblog.c
index 5519f91..9b975bc 100644
--- a/drivers/video/console/fblog.c
+++ b/drivers/video/console/fblog.c
@@ -33,6 +33,8 @@
 enum fblog_flags {
        FBLOG_KILLED,
        FBLOG_OPEN,
+       FBLOG_SUSPENDED,
+       FBLOG_BLANKED,
 };
 
 struct fblog_fb {
@@ -257,6 +259,7 @@ static int fblog_event(struct notifier_block *self, 
unsigned long action,
        struct fb_event *event = data;
        struct fb_info *info = event->info;
        struct fblog_fb *fb;
+       int *blank;
 
        switch(action) {
        case FB_EVENT_FB_REGISTERED:
@@ -284,6 +287,44 @@ static int fblog_event(struct notifier_block *self, 
unsigned long action,
                if (fb)
                        fblog_close(fb, true);
                break;
+       case FB_EVENT_SUSPEND:
+               /* This is called when the low-level display driver suspends the
+                * video system. We should not access the video system while it
+                * is suspended. This is called with the console lock held. */
+               mutex_lock(&fblog_registration_lock);
+               fb = fblog_fbs[info->node];
+               mutex_unlock(&fblog_registration_lock);
+
+               if (fb)
+                       set_bit(FBLOG_SUSPENDED, &fb->flags);
+               break;
+       case FB_EVENT_RESUME:
+               /* This is called when the low-level display driver resumes
+                * operating. It is called with the console lock held. */
+               mutex_lock(&fblog_registration_lock);
+               fb = fblog_fbs[info->node];
+               mutex_unlock(&fblog_registration_lock);
+
+               if (fb)
+                       clear_bit(FBLOG_SUSPENDED, &fb->flags);
+               break;
+       case FB_EVENT_BLANK:
+               /* This gets called _after_ the framebuffer was successfully
+                * blanked. The console-lock is always held while fb_blank is
+                * called and during this callback. */
+               mutex_lock(&fblog_registration_lock);
+               fb = fblog_fbs[info->node];
+               mutex_unlock(&fblog_registration_lock);
+
+               if (!fb)
+                       break;
+
+               blank = (int*)event->data;
+               if (*blank == FB_BLANK_UNBLANK)
+                       clear_bit(FBLOG_BLANKED, &fb->flags);
+               else
+                       set_bit(FBLOG_BLANKED, &fb->flags);
+               break;
        }
 
        return 0;
-- 
1.7.11.2

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