Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964904AbcKPGIv (ORCPT ); Wed, 16 Nov 2016 01:08:51 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:50040 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752169AbcKPGIs (ORCPT ); Wed, 16 Nov 2016 01:08:48 -0500 DMARC-Filter: OpenDMARC Filter v1.3.1 smtp.codeaurora.org 2370E614A1 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=pass smtp.mailfrom=architt@codeaurora.org Subject: Re: [PATCH] drm/bridge: analogix_dp: return error if transfer none byte To: Sean Paul , Jianqun Xu References: <1478168250-30858-1-git-send-email-jay.xu@rock-chips.com> Cc: Dave Airlie , =?UTF-8?B?546L5b6B5aKe?= , Tomeu Vizoso , Heiko Stuebner , huangtao@rock-chips.com, Masahiro Yamada , dri-devel , Linux Kernel Mailing List , linux-rockchip@lists.infradead.org From: Archit Taneja Message-ID: <46657d43-eed4-cd69-e5dc-110d78325bc1@codeaurora.org> Date: Wed, 16 Nov 2016 11:38:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2061 Lines: 57 On 11/15/2016 10:39 PM, Sean Paul wrote: > On Thu, Nov 3, 2016 at 3:17 AM, Jianqun Xu wrote: >> 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 >> Cc: Sean Paul >> Signed-off-by: Jianqun Xu > > Reviewed-by: Sean Paul queued to drm-misc. > >> --- >> 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 cd37ac0..303083a 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; >> } >> -- >> 1.9.1 >> >> -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project