queue-4.4/fbdev-sm712fb-fix-memory-frequency-by-avoiding-a-switch-case-fallthrough.patch

   1 From 9dc20113988b9a75ea6b3abd68dc45e2d73ccdab Mon Sep 17 00:00:00 2001
   2 From: Yifeng Li <tomli@tomli.me>
   3 Date: Tue, 2 Apr 2019 17:14:10 +0200
   4 Subject: fbdev: sm712fb: fix memory frequency by avoiding a switch/case fallthrough
   5
   6 From: Yifeng Li <tomli@tomli.me>
   7
   8 commit 9dc20113988b9a75ea6b3abd68dc45e2d73ccdab upstream.
   9
  10 A fallthrough in switch/case was introduced in f627caf55b8e ("fbdev:
  11 sm712fb: fix crashes and garbled display during DPMS modesetting"),
  12 due to my copy-paste error, which would cause the memory clock frequency
  13 for SM720 to be programmed to SM712.
  14
  15 Since it only reprograms the clock to a different frequency, it's only
  16 a benign issue without visible side-effect, so it also evaded Sudip
  17 Mukherjee's code review and regression tests. scripts/checkpatch.pl
  18 also failed to discover the issue, possibly due to nested switch
  19 statements.
  20
  21 This issue was found by Stephen Rothwell by building linux-next with
  22 -Wimplicit-fallthrough.
  23
  24 Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
  25 Fixes: f627caf55b8e ("fbdev: sm712fb: fix crashes and garbled display during DPMS modesetting")
  26 Signed-off-by: Yifeng Li <tomli@tomli.me>
  27 Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
  28 Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
  29 Cc: Kees Cook <keescook@chromium.org>
  30 Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  32
  33 ---
  34  drivers/video/fbdev/sm712fb.c |    1 +
  35  1 file changed, 1 insertion(+)
  36
  37 --- a/drivers/video/fbdev/sm712fb.c
  38 +++ b/drivers/video/fbdev/sm712fb.c
  39 @@ -898,6 +898,7 @@ static int smtc_blank(int blank_mode, st
  40                 case 0x712:
  41                         smtc_seqw(0x6a, 0x16);
  42                         smtc_seqw(0x6b, 0x02);
  43 +                       break;
  44                 case 0x720:
  45                         smtc_seqw(0x6a, 0x0d);
  46                         smtc_seqw(0x6b, 0x02);