From: Andrey Smirnov andrew.smirnov@gmail.com

[ Upstream commit e0655feaec62d5139b6b13a7b1bbb1ab8f1c2d83 ]

According to the datasheet tc358767 can transfer up to 16 bytes via its AUX channel, so the artificial limit of 8 appears to be too low. However only up to 15-bytes seem to be actually supported and trying to use 16-byte transfers results in transfers failing sporadically (with bogus status in case of I2C transfers), so limit it to 15.

Signed-off-by: Andrey Smirnov andrew.smirnov@gmail.com Reviewed-by: Andrzej Hajda a.hajda@samsung.com Reviewed-by: Tomi Valkeinen tomi.valkeinen@ti.com Cc: Andrzej Hajda a.hajda@samsung.com Cc: Laurent Pinchart Laurent.pinchart@ideasonboard.com Cc: Tomi Valkeinen tomi.valkeinen@ti.com Cc: Andrey Gusakov andrey.gusakov@cogentembedded.com Cc: Philipp Zabel p.zabel@pengutronix.de Cc: Cory Tusar cory.tusar@zii.aero Cc: Chris Healy cphealy@gmail.com Cc: Lucas Stach l.stach@pengutronix.de Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Andrzej Hajda a.hajda@samsung.com Link: https://patchwork.freedesktop.org/patch/msgid/20190619052716.16831-9-andrew.... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/tc358767.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 9705ca197b90d..cefa2c1685ba4 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -300,7 +300,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) { struct tc_data *tc = aux_to_tc(aux); - size_t size = min_t(size_t, 8, msg->size); + size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size); u8 request = msg->request & ~DP_AUX_I2C_MOT; u8 *buf = msg->buffer; u32 tmp = 0;