From patchwork Tue Oct 3 13:21:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Sharma, Shashank" X-Patchwork-Id: 9982807 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 7B7706029B for ; Tue, 3 Oct 2017 13:17:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6BB7D289AE for ; Tue, 3 Oct 2017 13:17:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 60DAD289B1; Tue, 3 Oct 2017 13:17:02 +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 E963C289AE for ; Tue, 3 Oct 2017 13:17:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 85A8F6E4A2; Tue, 3 Oct 2017 13:17:01 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4EDCC6E4A2 for ; Tue, 3 Oct 2017 13:17:00 +0000 (UTC) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP; 03 Oct 2017 06:16:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,474,1500966000"; d="scan'208,223";a="158805460" Received: from shashanks-linuxbox.iind.intel.com ([10.223.161.29]) by fmsmga006.fm.intel.com with ESMTP; 03 Oct 2017 06:16:58 -0700 From: Shashank Sharma To: intel-gfx@lists.freedesktop.org Date: Tue, 3 Oct 2017 18:51:04 +0530 Message-Id: <1507036865-16122-1-git-send-email-shashank.sharma@intel.com> X-Mailer: git-send-email 2.7.4 Subject: [Intel-gfx] [REBASE v3 1/2] 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 and respond. - changes one error log's level from ERROR->DEBUG as we want to call it an error only after all the retries are exhausted. V2: Addressed review comments from Jani (for loop for retry) V3: Addressed review comments from Imre (break on partial read too) Cc: Ville Syrjala Cc: Imre Deak Cc: Jani Nikula Signed-off-by: Shashank Sharma --- drivers/gpu/drm/drm_dp_dual_mode_helper.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c index 0ef9011..725b298 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -75,8 +75,16 @@ ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, }, }; int ret; + int retry; + + for (retry = 0; retry < 6; retry++) { + if (retry) + usleep_range(500, 1000); + ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); + if (ret >= 0) + break; + } - ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); if (ret < 0) return ret; if (ret != ARRAY_SIZE(msgs)) @@ -420,7 +428,7 @@ int drm_lspcon_get_mode(struct i2c_adapter *adapter, ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE, &data, sizeof(data)); if (ret < 0) { - DRM_ERROR("LSPCON read(0x80, 0x41) failed\n"); + DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n"); return -EFAULT; }