Commit 9e5c74f0 authored by Y.C. Chen's avatar Y.C. Chen Committed by Greg Kroah-Hartman

drm/ast: fixed reading monitor EDID not stable issue

[ Upstream commit 300625620314194d9e6d4f6dda71f2dc9cf62d9f ]

v1: over-sample data to increase the stability with some specific monitors
v2: refine to avoid infinite loop
v3: remove un-necessary "volatile" declaration

[airlied: fix two checkpatch warnings]
Signed-off-by: 's avatarY.C. Chen <yc_chen@aspeedtech.com>
Signed-off-by: 's avatarDave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1542858988-1127-1-git-send-email-yc_chen@aspeedtech.comSigned-off-by: 's avatarSasha Levin <sashal@kernel.org>
parent 1bb6e0cc
......@@ -954,9 +954,21 @@ static int get_clock(void *i2c_priv)
{
struct ast_i2c_chan *i2c = i2c_priv;
struct ast_private *ast = i2c->dev->dev_private;
uint32_t val;
uint32_t val, val2, count, pass;
count = 0;
pass = 0;
val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
do {
val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
if (val == val2) {
pass++;
} else {
pass = 0;
val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
}
} while ((pass < 5) && (count++ < 0x10000));
val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4;
return val & 1 ? 1 : 0;
}
......@@ -964,9 +976,21 @@ static int get_data(void *i2c_priv)
{
struct ast_i2c_chan *i2c = i2c_priv;
struct ast_private *ast = i2c->dev->dev_private;
uint32_t val;
uint32_t val, val2, count, pass;
count = 0;
pass = 0;
val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
do {
val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
if (val == val2) {
pass++;
} else {
pass = 0;
val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
}
} while ((pass < 5) && (count++ < 0x10000));
val = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5;
return val & 1 ? 1 : 0;
}
......@@ -979,7 +1003,7 @@ static void set_clock(void *i2c_priv, int clock)
for (i = 0; i < 0x10000; i++) {
ujcrb7 = ((clock & 0x01) ? 0 : 1);
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfe, ujcrb7);
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf4, ujcrb7);
jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x01);
if (ujcrb7 == jtemp)
break;
......@@ -995,7 +1019,7 @@ static void set_data(void *i2c_priv, int data)
for (i = 0; i < 0x10000; i++) {
ujcrb7 = ((data & 0x01) ? 0 : 1) << 2;
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xfb, ujcrb7);
ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf1, ujcrb7);
jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x04);
if (ujcrb7 == jtemp)
break;
......
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