[PATCH 1/3] drm/bridge: analogix_dp: properly handle zero sized AUX transactions

[Lucas Stach <l.stach@pengutronix.de>]

Address only transactions without any data are valid and should not
be flagged as short transactions. Simply return the message size when
no transaction errors occured.

CC: stable@vger.kernel.org
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 6a4f20fccf84..7b0bc9704eac 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1027,7 +1027,6 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 	u32 status_reg;
 	u8 *buffer = msg->buffer;
 	unsigned int i;
-	int num_transferred = 0;
 	int ret;
 
 	/* Buffer size of AUX CH is 16 bytes */
@@ -1079,7 +1078,6 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 			reg = buffer[i];
 			writel(reg, dp->reg_base + ANALOGIX_DP_BUF_DATA_0 +
 			       4 * i);
-			num_transferred++;
 		}
 	}
 
@@ -1127,7 +1125,6 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 			reg = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0 +
 				    4 * i);
 			buffer[i] = (unsigned char)reg;
-			num_transferred++;
 		}
 	}
 
@@ -1144,7 +1141,7 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 		 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
 		msg->reply = DP_AUX_NATIVE_REPLY_ACK;
 
-	return num_transferred > 0 ? num_transferred : -EBUSY;
+	return msg->size;
 
 aux_error:
 	/* if aux err happen, reset aux */
-- 
2.39.2