From ec64749b4e5e4e3abdb97141c4779ce105801dc8 Mon Sep 17 00:00:00 2001 From: zain wang Date: Mon, 13 Feb 2017 16:37:33 +0800 Subject: [PATCH] FROMLIST: drm/bridge: analogix_dp: Don't return -EBUSY when msg->size is 0 in aux transaction MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The analogix_dp_transfer() will return -EBUSY if num_transferred is zero. But sometimes we will send a bare address packet to start the transaction, like drm_dp_i2c_xfer() show: ...... /* Send a bare address packet to start the transaction. * Zero sized messages specify an address only (bare * address) transaction. */ msg.buffer = NULL; msg.size = 0; err = drm_dp_i2c_do_msg(aux, &msg); ...... In this case, the msg->size is zero, so the num_transferred will be zero too. We can't return -EBUSY here, let's we return num_transferred if num_transferred equals msg->size. BUG=chrome-os-partner:57501 TEST="gooftool probe --comps display_panel" Change-Id: Ie09f26b2c31e2406d21233afd8677337de5e77f2 Signed-off-by: zain wang (am from https://patchwork.kernel.org/patch/9569045/) Reviewed-on: https://chromium-review.googlesource.com/414674 Commit-Ready: Caesar Wang Tested-by: 征增 王 Reviewed-by: Sean Paul --- 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 08eadcbeb346..ed1c00564b2a 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c @@ -1134,7 +1134,7 @@ 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 (num_transferred == msg->size) ? num_transferred : -EBUSY; aux_error: /* if aux err happen, reset aux */