releases/4.9.146/drm-ast-fixed-reading-monitor-edid-not-stable-issue.patch

   1 From 924770877b5ec2917e3e3bcce1d3a8a1c20238b3 Mon Sep 17 00:00:00 2001
   2 From: "Y.C. Chen" <yc_chen@aspeedtech.com>
   3 Date: Thu, 22 Nov 2018 11:56:28 +0800
   4 Subject: drm/ast: fixed reading monitor EDID not stable issue
   5
   6 [ Upstream commit 300625620314194d9e6d4f6dda71f2dc9cf62d9f ]
   7
   8 v1: over-sample data to increase the stability with some specific monitors
   9 v2: refine to avoid infinite loop
  10 v3: remove un-necessary "volatile" declaration
  11
  12 [airlied: fix two checkpatch warnings]
  13
  14 Signed-off-by: Y.C. Chen <yc_chen@aspeedtech.com>
  15 Signed-off-by: Dave Airlie <airlied@redhat.com>
  16 Link: https://patchwork.freedesktop.org/patch/msgid/1542858988-1127-1-git-send-email-yc_chen@aspeedtech.com
  17 Signed-off-by: Sasha Levin <sashal@kernel.org>
  18 ---
  19  drivers/gpu/drm/ast/ast_mode.c | 36 ++++++++++++++++++++++++++++------
  20  1 file changed, 30 insertions(+), 6 deletions(-)
  21
  22 diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
  23 index 57205016b04a..201874b96dd6 100644
  24 --- a/drivers/gpu/drm/ast/ast_mode.c
  25 +++ b/drivers/gpu/drm/ast/ast_mode.c
  26 @@ -954,9 +954,21 @@ static int get_clock(void *i2c_priv)
  27  {
  28         struct ast_i2c_chan *i2c = i2c_priv;
  29         struct ast_private *ast = i2c->dev->dev_private;
  30 -       uint32_t val;
  31 +       uint32_t val, val2, count, pass;
  32 +
  33 +       count = 0;
  34 +       pass = 0;
  35 +       val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
  36 +       do {
  37 +               val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
  38 +               if (val == val2) {
  39 +                       pass++;
  40 +               } else {
  41 +                       pass = 0;
  42 +                       val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
  43 +               }
  44 +       } while ((pass < 5) && (count++ < 0x10000));
  45
  46 -       val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4;
  47         return val & 1 ? 1 : 0;
  48  }
  49
  50 @@ -964,9 +976,21 @@ static int get_data(void *i2c_priv)
  51  {
  52         struct ast_i2c_chan *i2c = i2c_priv;
  53         struct ast_private *ast = i2c->dev->dev_private;
  54 -       uint32_t val;
  55 +       uint32_t val, val2, count, pass;
  56 +
  57 +       count = 0;
  58 +       pass = 0;
  59 +       val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
  60 +       do {
  61 +               val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
  62 +               if (val == val2) {
  63 +                       pass++;
  64 +               } else {
  65 +                       pass = 0;
  66 +                       val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
  67 +               }
  68 +       } while ((pass < 5) && (count++ < 0x10000));
  69
  70 -       val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5;
  71         return val & 1 ? 1 : 0;
  72  }
  73
  74 @@ -979,7 +1003,7 @@ static void set_clock(void *i2c_priv, int clock)
  75
  76         for (i = 0; i < 0x10000; i++) {
  77                 ujcrb7 = ((clock & 0x01) ? 0 : 1);
  78 -               ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfe, ujcrb7);
  79 +               ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf4, ujcrb7);
  80                 jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x01);
  81                 if (ujcrb7 == jtemp)
  82                         break;
  83 @@ -995,7 +1019,7 @@ static void set_data(void *i2c_priv, int data)
  84
  85         for (i = 0; i < 0x10000; i++) {
  86                 ujcrb7 = ((data & 0x01) ? 0 : 1) << 2;
  87 -               ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfb, ujcrb7);
  88 +               ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf1, ujcrb7);
  89                 jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x04);
  90                 if (ujcrb7 == jtemp)
  91                         break;
  92 --
  93 2.19.1
  94