[PATCH 08/11] fblog: cache framebuffer BLANK and SUSPEND states

From: David Herrmann
Date: Sun Aug 12 2012 - 10:53:36 EST


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.herrmann@xxxxxxxxxxxxxx>
---
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 aed77dc..8bcd0ce 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 {
@@ -264,6 +266,7 @@ 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:
@@ -291,6 +294,44 @@ 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;
--
1.7.11.4

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