From: Yifeng Li <[email protected]>

commit ec1587d5073f29820e358f3a383850d61601d981 upstream.

When the machine is booted in VGA mode, loading sm712fb would cause
a glitch of random pixels shown on the screen. To prevent it from
happening, we first clear the entire framebuffer, and we also need
to stop calling smtcfb_setmode() during initialization, the fbdev
layer will call it for us later when it's ready.

Signed-off-by: Yifeng Li <[email protected]>
Tested-by: Sudip Mukherjee <[email protected]>
Cc: Teddy Wang <[email protected]>
Cc: <[email protected]>  # v4.4+
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/video/fbdev/sm712fb.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/video/fbdev/sm712fb.c
+++ b/drivers/video/fbdev/sm712fb.c
@@ -1493,7 +1493,11 @@ static int smtcfb_pci_probe(struct pci_d
        if (err)
                goto failed;
 
-       smtcfb_setmode(sfb);
+       /*
+        * The screen would be temporarily garbled when sm712fb takes over
+        * vesafb or VGA text mode. Zero the framebuffer.
+        */
+       memset_io(sfb->lfb, 0, sfb->fb->fix.smem_len);
 
        err = register_framebuffer(info);
        if (err < 0)


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