From 423c5088e8dc6793ea610a12e4cd7bcc9b9cd8f2 Mon Sep 17 00:00:00 2001
From: Icenowy Zheng <icenowy@aosc.io>
Date: Sat, 22 Feb 2020 00:51:27 +0800
Subject: drm/bridge: analogix-anx6345: fix set of link bandwidth
Git-commit: 2be30d34a387b8d97cc1b4be1223bfe0b75a0812
Patch-mainline: v5.6-rc5
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Current code tries to store the link rate (in bps, which is a big
number) in a u8, which surely overflow. Then it's converted back to
bandwidth code (which is thus 0) and written to the chip.
The code sometimes works because the chip will automatically fallback to
the lowest possible DP link rate (1.62Gbps) when get the invalid value.
However, on the eDP panel of Olimex TERES-I, which wants 2.7Gbps link,
it failed.
As we had already read the link bandwidth as bandwidth code in earlier
code (to check whether it is supported), use it when setting bandwidth,
instead of converting it to link rate and then converting back.
Fixes: e1cff82c1097 ("drm/bridge: fix anx6345 compilation for v5.5")
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Torsten Duwe <duwe@lst.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Icenowy Zheng <icenowy@aosc.io>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200221165127.813325-1-icenowy@aosc.io
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/bridge/analogix/analogix-anx6345.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
index 56f55c53abfd..2dfa2fd2a23b 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
@@ -210,8 +210,7 @@ static int anx6345_dp_link_training(struct anx6345 *anx6345)
if (err)
return err;
- dpcd[0] = drm_dp_max_link_rate(anx6345->dpcd);
- dpcd[0] = drm_dp_link_rate_to_bw_code(dpcd[0]);
+ dpcd[0] = dp_bw;
err = regmap_write(anx6345->map[I2C_IDX_DPTX],
SP_DP_MAIN_LINK_BW_SET_REG, dpcd[0]);
if (err)
--
2.28.0