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[2620:137:e000::1:20]) by mx.google.com with ESMTP id cj25-20020a056a00299900b0067b77e7f46csi12204628pfb.187.2023.07.25.14.22.51; Tue, 25 Jul 2023 14:23:04 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=YEAWKLjW; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231289AbjGYUhw (ORCPT + 99 others); Tue, 25 Jul 2023 16:37:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231481AbjGYUhc (ORCPT ); Tue, 25 Jul 2023 16:37:32 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B4412724 for ; Tue, 25 Jul 2023 13:37:17 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id 98e67ed59e1d1-2682e33509bso1118614a91.1 for ; Tue, 25 Jul 2023 13:37:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1690317437; x=1690922237; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=xwFg3zsWqs3v6aVHVxyVzqQhxIAjeJPLZHSa2wy+9Ws=; b=YEAWKLjWr/L+vjIF/bsCu89PM2D3kj1DnycpkaOmYXw/LwIxNJYxpJT5SL8xqbGgfh /blJGOH8ksO8YsSrNyYG9OCGGJzuY7bFfdwIwKg+FTXFyHptWrhtVCmkpQuWGGvzsS+H 6AxQXIA/4EMMdpwOdUybjh0Pskkt21KKVgBgc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690317437; x=1690922237; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=xwFg3zsWqs3v6aVHVxyVzqQhxIAjeJPLZHSa2wy+9Ws=; b=XY7gz6fXcjPRq9xS0ZnvSFZcNurkJQfT1irDfsw/AH64bE0Z1lo6lCfFcF/dzZd69S 7RpxI/ffMlrycX5TOGBiFu3bqMKaoYmfgVxoDBSnKAfBiKFbY8ElDXj8982wgnIm80VN aqLMF/bWFFcEgAyXMQjndwxcKjchupkAqKdT7DY6/i7TX4rnzeSeg0CwABF74DqA95TW oAHSJrWICFQj2Yb++6rAOk27wisJfk4lNgvQCyApmVuEw+V+QtE7/V0Hjw7x1DIChvdh dPWg9bnnYtTvVKQmjIZ1qePpfbc+ma5rAX9RfWE95vlbaBbzNbAEi94zWuS9jWemF18m pHmQ== X-Gm-Message-State: ABy/qLZ4K6nX93yj24h4mDo4pjOM0Mg++gAGuDgiFyx13OPEJC65l7ln E82o/+iEM2kDAEuDQoCjeI/XsQ== X-Received: by 2002:a17:90a:a406:b0:268:7eb:f599 with SMTP id y6-20020a17090aa40600b0026807ebf599mr232634pjp.30.1690317437028; Tue, 25 Jul 2023 13:37:17 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:c363:4681:f5b8:301]) by smtp.gmail.com with ESMTPSA id bg1-20020a17090b0d8100b002676e961261sm1396951pjb.1.2023.07.25.13.37.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jul 2023 13:37:16 -0700 (PDT) From: Douglas Anderson To: Jiri Kosina , Benjamin Tissoires , Bjorn Andersson , Konrad Dybcio , Rob Herring , Frank Rowand , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Sam Ravnborg , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Cc: cros-qcom-dts-watchers@chromium.org, Chris Morgan , linux-input@vger.kernel.org, hsinyi@google.com, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dmitry Torokhov , devicetree@vger.kernel.org, Daniel Vetter , yangcong5@huaqin.corp-partner.google.com, Douglas Anderson Subject: [PATCH v3 09/10] HID: i2c-hid: Do panel follower work on the system_wq Date: Tue, 25 Jul 2023 13:34:44 -0700 Message-ID: <20230725133443.v3.9.I962bb462ede779005341c49320740ed95810021d@changeid> X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog In-Reply-To: <20230725203545.2260506-1-dianders@chromium.org> References: <20230725203545.2260506-1-dianders@chromium.org> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772429178187793660 X-GMAIL-MSGID: 1772429178187793660 Turning on an i2c-hid device can be a slow process. This is why i2c-hid devices use PROBE_PREFER_ASYNCHRONOUS. Unfortunately, when we're a panel follower the i2c-hid power up sequence now blocks the power on of the panel. Let's fix that by scheduling the work on the system_wq. Signed-off-by: Douglas Anderson --- (no changes since v2) Changes in v2: - ihid_core_panel_prepare_work() is now static. - Improve documentation for smp_wmb(). drivers/hid/i2c-hid/i2c-hid-core.c | 50 +++++++++++++++++++++++++++--- 1 file changed, 46 insertions(+), 4 deletions(-) diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index fa6d1f624342..6940e74d8acb 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -110,7 +110,9 @@ struct i2c_hid { struct i2chid_ops *ops; struct drm_panel_follower panel_follower; + struct work_struct panel_follower_prepare_work; bool is_panel_follower; + bool prepare_work_finished; }; static const struct i2c_hid_quirks { @@ -1062,10 +1064,12 @@ static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid) return ret; } -static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower) +static void ihid_core_panel_prepare_work(struct work_struct *work) { - struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower); + struct i2c_hid *ihid = container_of(work, struct i2c_hid, + panel_follower_prepare_work); struct hid_device *hid = ihid->hid; + int ret; /* * hid->version is set on the first power up. If it's still zero then @@ -1073,15 +1077,52 @@ static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower) * steps. */ if (!hid->version) - return i2c_hid_core_initial_power_up(ihid); + ret = i2c_hid_core_initial_power_up(ihid); + else + ret = i2c_hid_core_resume(ihid); - return i2c_hid_core_resume(ihid); + if (ret) + dev_warn(&ihid->client->dev, "Power on failed: %d\n", ret); + else + WRITE_ONCE(ihid->prepare_work_finished, true); + + /* + * The work APIs provide a number of memory ordering guarantees + * including one that says that memory writes before schedule_work() + * are always visible to the work function, but they don't appear to + * guarantee that a write that happened in the work is visible after + * cancel_work_sync(). We'll add a write memory barrier here to match + * with i2c_hid_core_panel_unpreparing() to ensure that our write to + * prepare_work_finished is visible there. + */ + smp_wmb(); +} + +static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower) +{ + struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower); + + /* + * Powering on a touchscreen can be a slow process. Queue the work to + * the system workqueue so we don't block the panel's power up. + */ + WRITE_ONCE(ihid->prepare_work_finished, false); + schedule_work(&ihid->panel_follower_prepare_work); + + return 0; } static int i2c_hid_core_panel_unpreparing(struct drm_panel_follower *follower) { struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower); + cancel_work_sync(&ihid->panel_follower_prepare_work); + + /* Match with ihid_core_panel_prepare_work() */ + smp_rmb(); + if (!READ_ONCE(ihid->prepare_work_finished)) + return 0; + return i2c_hid_core_suspend(ihid); } @@ -1149,6 +1190,7 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops, init_waitqueue_head(&ihid->wait); mutex_init(&ihid->reset_lock); + INIT_WORK(&ihid->panel_follower_prepare_work, ihid_core_panel_prepare_work); /* we need to allocate the command buffer without knowing the maximum * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the