From: Yifeng Li tomli@tomli.me
commit 9dc20113988b9a75ea6b3abd68dc45e2d73ccdab upstream.
A fallthrough in switch/case was introduced in f627caf55b8e ("fbdev: sm712fb: fix crashes and garbled display during DPMS modesetting"), due to my copy-paste error, which would cause the memory clock frequency for SM720 to be programmed to SM712.
Since it only reprograms the clock to a different frequency, it's only a benign issue without visible side-effect, so it also evaded Sudip Mukherjee's code review and regression tests. scripts/checkpatch.pl also failed to discover the issue, possibly due to nested switch statements.
This issue was found by Stephen Rothwell by building linux-next with -Wimplicit-fallthrough.
Reported-by: Stephen Rothwell sfr@canb.auug.org.au Fixes: f627caf55b8e ("fbdev: sm712fb: fix crashes and garbled display during DPMS modesetting") Signed-off-by: Yifeng Li tomli@tomli.me Cc: Sudip Mukherjee sudipm.mukherjee@gmail.com Cc: "Gustavo A. R. Silva" gustavo@embeddedor.com Cc: Kees Cook keescook@chromium.org Signed-off-by: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/video/fbdev/sm712fb.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -898,6 +898,7 @@ static int smtc_blank(int blank_mode, st case 0x712: smtc_seqw(0x6a, 0x16); smtc_seqw(0x6b, 0x02); + break; case 0x720: smtc_seqw(0x6a, 0x0d); smtc_seqw(0x6b, 0x02);