ENGR00308397 video: mxsfb: unblank fb explicitly in probe()

The following two commits for backlight core driver introduce
an usecount for each backlight device and on/off usage info of
each framebuffer associated with it so that we may enable/disable
a backlight device when necessary.
commit dcb7e61054b959dc4d601a96cce5cc85ad1568ef
commit b48b097319587422195adc3f8b2b3b0c067943cc
The problem is that some framebuffer drivers would enable their
display controllers in probe() and some backlight device drivers
would enable their backlights in probe() so that the backlight
device usecounts and the on/off usage info of framebuffers are
out of counting at the probing stage.  This causes a backlight
cannot be disabled by blanking the relevant framebuffer(s) before
any fb unblanking operation, though it's quite reasonable for the
userland to unblank the framebuffer(s) before using it.  In order
to avoid the potential unnecessary lighten backlight left behind
for the mxsfb driver, this patch unblanks framebuffer explicitly
in probe() since the LCDIF display controller is actually enabled
there.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit 61667ae1430849af17e2431bbe9290295e0ec492)

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index 60a760b0a6da..c9fcd8d0af0d 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -1368,10 +1368,20 @@ static int mxsfb_probe(struct platform_device *pdev)
                 goto fb_destroy;
         }
 
+        console_lock();
+        ret = fb_blank(fb_info, FB_BLANK_UNBLANK);
+        console_unlock();
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to unblank framebuffer\n");
+                goto fb_unregister;
+        }
+
         dev_info(&pdev->dev, "initialized\n");
 
         return 0;
 
+fb_unregister:
+        unregister_framebuffer(fb_info);
 fb_destroy:
         if (host->enabled)
                 clk_disable_unprepare(host->clk_pix);