target/linux/brcm2708/patches-4.14/950-0128-panel-raspberrypi-touchscreen-Round-up-clk-rate-to-f.patch

   1 From 7f98947db09ad419ca73082230ade1f29f18bd82 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 6 Mar 2017 12:17:16 -0800
   4 Subject: [PATCH 128/454] panel-raspberrypi-touchscreen: Round up clk rate to
   5  fix DSI panel.
   6
   7 Commit 488f9bc8e3def93e0baef53cee2026c2cb0d8956 slightly increased the
   8 reported rate of PLLD, so the clk driver decided that PLLD/3/8 was now
   9 higher than our requested pixel clock rate and rejected it in favor of
  10 PLLD/4/8, which then ran the pixel clock way out of spec.
  11
  12 By bumping the requested clock rate just slightly, we get back to
  13 PLLD/3/8 like we wanted and the panel displays content again.
  14
  15 Signed-off-by: Eric Anholt <eric@anholt.net>
  16 ---
  17  drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 7 ++++++-
  18  1 file changed, 6 insertions(+), 1 deletion(-)
  19
  20 --- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
  21 +++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
  22 @@ -220,7 +220,12 @@ static const struct drm_display_mode rpi
  23  #define HBP         46
  24  #define HFP         ((PIXEL_CLOCK / (VTOTAL * VREFRESH)) - (HACT + HSW + HBP))
  25
  26 -               .clock = PIXEL_CLOCK / 1000,
  27 +               /* Round up the pixel clock a bit (10khz), so that the
  28 +                * "don't run things faster than the requested clock
  29 +                * rate" rule of the clk driver doesn't reject the
  30 +                * divide-by-3 mode due to rounding error.
  31 +                */
  32 +               .clock = PIXEL_CLOCK / 1000 + 10,
  33                 .hdisplay = HACT,
  34                 .hsync_start = HACT + HFP,
  35                 .hsync_end = HACT + HFP + HSW,