From: Torsten Duwe <duwe@xxxxxx> commit 3e138a63d6674a4567a018a31e467567c40b14d5 upstream. drm_dp_link_rate_to_bw_code and ...bw_code_to_link_rate simply divide by and multiply with 27000, respectively. Avoid an overflow in the u8 dpcd[0] and the multiply+divide alltogether. Signed-off-by: Torsten Duwe <duwe@xxxxxx> Fixes: ff1e8fb68ea0 ("drm/bridge: analogix-anx78xx: Avoid drm_dp_link helpers") Cc: Thierry Reding <treding@xxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx> Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx> Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx> Cc: Jonas Karlman <jonas@xxxxxxxxx> Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v5.5+ Reviewed-by: Thierry Reding <treding@xxxxxxxxxx> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20200218155744.9675368BE1@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c @@ -722,10 +722,9 @@ static int anx78xx_dp_link_training(stru if (err) return err; - dpcd[0] = drm_dp_max_link_rate(anx78xx->dpcd); - dpcd[0] = drm_dp_link_rate_to_bw_code(dpcd[0]); err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], - SP_DP_MAIN_LINK_BW_SET_REG, dpcd[0]); + SP_DP_MAIN_LINK_BW_SET_REG, + anx78xx->dpcd[DP_MAX_LINK_RATE]); if (err) return err;