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From: "Y.C. Chen" <yacheng600221@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: airlied@redhat.com, eich@suse.com, imirkin@alum.mit.edu,
	yc_chen@aspeedtech.com, stable@vger.kernel.org
Subject: [[PATCH v2]] drm/ast: fixed reading monitor EDID not stable issue
Date: Wed, 31 Oct 2018 09:31:14 +0800	[thread overview]
Message-ID: <1540949474-1269-1-git-send-email-yc_chen@aspeedtech.com> (raw)
In-Reply-To: <1540879231-4243-1-git-send-email-yc_chen@aspeedtech.com>

From: "Y.C. Chen" <yc_chen@aspeedtech.com>

v1: over-sample data to increase the stability with some specific monitors
v2: refine to avoid infinite loop

Signed-off-by: Y.C. Chen <yc_chen@aspeedtech.com>
---
 drivers/gpu/drm/ast/ast_mode.c | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 5e77d45..092e9a7 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -972,9 +972,20 @@ 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;
+	volatile 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;
 }
 
@@ -982,9 +993,20 @@ 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;
+	volatile 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;
 }
 
@@ -997,7 +1019,7 @@ 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;
@@ -1013,7 +1035,7 @@ 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;
-- 
1.8.3.1

  parent reply	other threads:[~2018-10-31 10:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-30  6:00 [PATCH] drm/ast: fixed reading monitor EDID not stable issue Y.C. Chen
2018-10-30 13:01 ` Ilia Mirkin
2018-10-31  1:31 ` Y.C. Chen [this message]
2018-11-22  1:15   ` [[PATCH v2]] " Dave Airlie
2018-11-22  1:42     ` 陳雅正
2018-11-22  2:48       ` Dave Airlie
2018-11-22  3:56   ` [PATCH v3] " Y.C. Chen

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