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Commit aa17edff authored by Dave Airlie's avatar Dave Airlie
Browse files

drm/dp_helper: don't return EPROTO for defers (v2) 



If we get a msg.reply of REPLY_DEFER, we also get an err of 0
so we fail reads with 0 < size and return -EPROTO instead of trying
again.

v2: same fix in i2c code.

Found writing MST support.

Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent f4d1b021

drivers/gpu/drm/drm_dp_helper.c

+4 −4
Original line number Diff line number Diff line
@@ -386,11 +386,11 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, 
			return err;

		}



		if (err < size)

			return -EPROTO;



		switch (msg.reply & DP_AUX_NATIVE_REPLY_MASK) {

		case DP_AUX_NATIVE_REPLY_ACK:

			if (err < size)

				return -EPROTO;

			return err;



		case DP_AUX_NATIVE_REPLY_NACK:
@@ -599,8 +599,6 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) 
			return err;

		}



		if (err < msg->size)

			return -EPROTO;



		switch (msg->reply & DP_AUX_NATIVE_REPLY_MASK) {

		case DP_AUX_NATIVE_REPLY_ACK:
@@ -639,6 +637,8 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) 
			 * Both native ACK and I2C ACK replies received. We

			 * can assume the transfer was successful.

			 */

			if (err < msg->size)

				return -EPROTO;

			return 0;



		case DP_AUX_I2C_REPLY_NACK: