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@xxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # v4.4+ --- 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 1a3d232c2916..e8149f0f47d5 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1493,7 +1493,11 @@ 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) -- 2.20.1
