From: Yifeng Li tomli@tomli.me

[ Upstream commit ec1587d5073f29820e358f3a383850d61601d981 ]

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 tomli@tomli.me Tested-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Cc: Teddy Wang teddy.wang@siliconmotion.com Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/fbdev/sm712fb.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c index 2539c1e6facb4..6a30714a18632 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1498,7 +1498,11 @@ static int smtcfb_pci_probe(struct pci_dev *pdev, 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)