From: Dirk Eibach dirk.eibach@gdsys.cc
DP501 only supports DP 1.1a. Limit settings for link bandwidth and lane count to values allowed by DP 1.1a.
Signed-off-by: Dirk Eibach dirk.eibach@gdsys.cc ---
board/gdsys/common/dp501.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/board/gdsys/common/dp501.c b/board/gdsys/common/dp501.c index 0389fd1..d35aee0 100644 --- a/board/gdsys/common/dp501.c +++ b/board/gdsys/common/dp501.c @@ -40,11 +40,29 @@ static int dp501_detect_cable_adapter(u8 addr) static void dp501_link_training(u8 addr) { u8 val; + u8 link_bw; + u8 max_lane_cnt; + u8 lane_cnt;
val = i2c_reg_read(addr, 0x51); - i2c_reg_write(addr, 0x5d, val); /* set link_bw */ + if (val >= 0x0a) + link_bw = 0x0a; + else + link_bw = 0x06; + if (link_bw != val) + printf("DP sink supports %d Mbps link rate, set to %d Mbps\n", + val * 270, link_bw * 270); + i2c_reg_write(addr, 0x5d, link_bw); /* set link_bw */ val = i2c_reg_read(addr, 0x52); - i2c_reg_write(addr, 0x5e, val); /* set lane_cnt */ + max_lane_cnt = val & 0x1f; + if (max_lane_cnt >= 4) + lane_cnt = 4; + else + lane_cnt = max_lane_cnt; + if (lane_cnt != max_lane_cnt) + printf("DP sink supports %d lanes, set to %d lanes\n", + max_lane_cnt, lane_cnt); + i2c_reg_write(addr, 0x5e, lane_cnt | (val & 0x80)); /* set lane_cnt */ val = i2c_reg_read(addr, 0x53); i2c_reg_write(addr, 0x5c, val); /* set downspread_ctl */