From 19423ba7109a94dfb3beda88f9dcced54e4831d8 Mon Sep 17 00:00:00 2001 From: Jianqun Xu Date: Wed, 16 Nov 2016 08:13:39 +0800 Subject: [PATCH] drm/bridge: analogix_dp: return error if transfer none byte Reference from drm_dp_aux description (about transfer): Upon success, the implementation should return the number of payload bytes that were transferred, or a negative error-code on failure. Helpers propagate errors from the .transfer() function, with the exception of the -EBUSY error, which causes a transaction to be retried. On a short, helpers will return -EPROTO to make it simpler to check for failure. The analogix_dp_transfer will return num_transferred, but if there is none byte been transferred, the return value will be 0, which means success, we should return error-code if transfer none byte. for (retry = 0; retry < 32; retry++) { err = aux->transfer(aux, &msg); if (err < 0) { if (err == -EBUSY) continue; goto unlock; } } Cc: zain wang Reviewed-by: Sean Paul Signed-off-by: Jianqun Xu Signed-off-by: Archit Taneja Link: http://patchwork.freedesktop.org/patch/msgid/1479255219-7243-1-git-send-email-jay.xu@rock-chips.com --- drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c index cd37ac058675..303083ad28e3 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c @@ -1162,5 +1162,5 @@ 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; + return num_transferred > 0 ? num_transferred : -EBUSY; } -- 2.20.1