[PATCH] Fix radeon DDC regression

When radeonfb was changed to use the new "generic" ddc, a bit of
code initializing the GPIO lines was lost, causing it to not work
if the firmware didn't configure them properly, which seems to
happen on some cards.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/video/aty/radeon_i2c.c

@@ -139,7 +139,13 @@ void radeon_delete_i2c_busses(struct radeonfb_info *rinfo)
 int radeon_probe_i2c_connector(struct radeonfb_info *rinfo, int conn,
 			       u8 **out_edid)
 {
-	u8 *edid = fb_ddc_read(&rinfo->i2c[conn-1].adapter);
+	u32 reg = rinfo->i2c[conn-1].ddc_reg;
+	u8 *edid;
+
+	OUTREG(reg, INREG(reg) &
+			~(VGA_DDC_DATA_OUTPUT | VGA_DDC_CLK_OUTPUT));
+
+	edid = fb_ddc_read(&rinfo->i2c[conn-1].adapter);
 
 	if (out_edid)
 		*out_edid = edid;