[PATCH] revert "nvidiafb: use generic ddc reading"

Olaf reports that this gave him a black screen.

Cc: Olaf Hering <olaf@aepfle.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 42 insertions, 3 deletions

diff --git a/drivers/video/nvidia/nv_i2c.c b/drivers/video/nvidia/nv_i2c.c
index e48de3c9fd1..19eef3a0902 100644
--- a/drivers/video/nvidia/nv_i2c.c
+++ b/drivers/video/nvidia/nv_i2c.c
@@ -160,12 +160,51 @@ void nvidia_delete_i2c_busses(struct nvidia_par *par)
 
 }
 
+static u8 *nvidia_do_probe_i2c_edid(struct nvidia_i2c_chan *chan)
+{
+	u8 start = 0x0;
+	struct i2c_msg msgs[] = {
+		{
+		 .addr = 0x50,
+		 .len = 1,
+		 .buf = &start,
+		 }, {
+		     .addr = 0x50,
+		     .flags = I2C_M_RD,
+		     .len = EDID_LENGTH,
+		     },
+	};
+	u8 *buf;
+
+	if (!chan->par)
+		return NULL;
+
+	buf = kmalloc(EDID_LENGTH, GFP_KERNEL);
+	if (!buf) {
+		dev_warn(&chan->par->pci_dev->dev, "Out of memory!\n");
+		return NULL;
+	}
+	msgs[1].buf = buf;
+
+	if (i2c_transfer(&chan->adapter, msgs, 2) == 2)
+		return buf;
+	dev_dbg(&chan->par->pci_dev->dev, "Unable to read EDID block.\n");
+	kfree(buf);
+	return NULL;
+}
+
 int nvidia_probe_i2c_connector(struct fb_info *info, int conn, u8 **out_edid)
 {
 	struct nvidia_par *par = info->par;
-	u8 *edid;
-
-	edid = fb_ddc_read(&par->chan[conn - 1].adapter);
+	u8 *edid = NULL;
+	int i;
+
+	for (i = 0; i < 3; i++) {
+		/* Do the real work */
+		edid = nvidia_do_probe_i2c_edid(&par->chan[conn - 1]);
+		if (edid)
+			break;
+	}
 
 	if (!edid && conn == 1) {
 		/* try to get from firmware */