From patchwork Tue Aug 22 14:53:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Sharma, Shashank" X-Patchwork-Id: 9915445 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 44143603F9 for ; Tue, 22 Aug 2017 14:51:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1C749288B4 for ; Tue, 22 Aug 2017 14:51:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 118BF288CF; Tue, 22 Aug 2017 14:51:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CD5D4288B4 for ; Tue, 22 Aug 2017 14:51:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 94B4E6E3F4; Tue, 22 Aug 2017 14:51:01 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 13A056E3E9 for ; Tue, 22 Aug 2017 14:50:57 +0000 (UTC) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Aug 2017 07:50:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,412,1498546800"; d="scan'208,223";a="1186918321" Received: from shashanks-linuxbox.iind.intel.com ([10.223.161.29]) by fmsmga001.fm.intel.com with ESMTP; 22 Aug 2017 07:50:36 -0700 From: Shashank Sharma To: intel-gfx@lists.freedesktop.org Date: Tue, 22 Aug 2017 20:23:51 +0530 Message-Id: <1503413631-18438-4-git-send-email-shashank.sharma@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503413631-18438-1-git-send-email-shashank.sharma@intel.com> References: <1503413631-18438-1-git-send-email-shashank.sharma@intel.com> Subject: [Intel-gfx] [PATCH 3/3] drm: Add retries for dp dual mode read X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP From the CI builds, its been observed that during a driver reload/insert, dp dual mode read function sometimes fails to read from dual mode devices (like LSPCON) over i2c-over-aux channel. This patch adds some delay and few retries, allowing a scope for these devices to settle down. V3: Introduced this patch Cc: Ville Syrjala Cc: Imre Deak Signed-off-by: Shashank Sharma --- drivers/gpu/drm/drm_dp_dual_mode_helper.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c index fc8c7ac..bb34ff8 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -75,8 +75,15 @@ ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, }, }; int ret; + int retry; + + for (retry = 5; ; retry--) { + ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); + if (ret > 0 || !retry) + break; + usleep_range(500, 1000); + } - ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); if (ret < 0) return ret; if (ret != ARRAY_SIZE(msgs))