From patchwork Mon Apr 19 22:55:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 12212803 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FA84C43460 for ; Mon, 19 Apr 2021 22:57:01 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0B04E60FF1 for ; Mon, 19 Apr 2021 22:57:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B04E60FF1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9A7406E45E; Mon, 19 Apr 2021 22:56:59 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4F7536E462 for ; Mon, 19 Apr 2021 22:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618873017; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=slxebeoTrun/9X4zqXX+vRn3QZNp09V1kZPDZBahFDo=; b=NHlfOhvovvqUIYvinRpmz/RQSrgtcDbWJHBrVtGKxNAcPEJ+uBaLvfxAA/sgyH1Bwqwe8T VtRDqCfFd/6w5PcnW2kCn/a7mTP7fgn8UEXP1Hj0dqZHfGa88XLHx/SRcBjWUiVih5M0G4 g6bOC2QZZ/d6Frs/MPWhDblT4FG/1zQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-435-gR_fhCOHP7W6uN6xLZVolw-1; Mon, 19 Apr 2021 18:56:55 -0400 X-MC-Unique: gR_fhCOHP7W6uN6xLZVolw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 31152501F0; Mon, 19 Apr 2021 22:56:49 +0000 (UTC) Received: from Ruby.lyude.net (ovpn-119-153.rdu2.redhat.com [10.10.119.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id A86665C1C4; Mon, 19 Apr 2021 22:56:42 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Jani Nikula , Rodrigo Vivi , Thomas Zimmermann , Thierry Reding Subject: [PATCH v3 06/20] drm/dp: Add backpointer to drm_device in drm_dp_aux Date: Mon, 19 Apr 2021 18:55:08 -0400 Message-Id: <20210419225523.184856-7-lyude@redhat.com> In-Reply-To: <20210419225523.184856-1-lyude@redhat.com> References: <20210419225523.184856-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lyude@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Neil Armstrong , David Airlie , =?utf-8?q?Guido_G=C3=BCnther?= , Oleg Vasilev , Meenakshikumar Somasundaram , Andrzej Hajda , Aurabindo Pillai , Laurent Pinchart , Sam Ravnborg , Emil Velikov , Tomi Valkeinen , Parshuram Thombare , Rodrigo Siqueira , Michal Simek , Jonathan Hunter , Luben Tuikov , Ben Skeggs , Swapnil Jakhade , Thierry Reding , Jonas Karlman , Leo Li , "open list:DRM DRIVER FOR MSM ADRENO GPU" , Joe Perches , "open list:DRM DRIVERS FOR NVIDIA TEGRA" , Mikita Lipski , Sean Paul , "moderated list:ARM/ZYNQ ARCHITECTURE" , Jernej Skrabec , Chris Park , Eryk Brol , Hyun Kwon , open list , Robert Foss , Julia Lawall , Wayne Lin , Alex Deucher , "open list:DRM DRIVER FOR MSM ADRENO GPU" , =?utf-8?q?Christian_K=C3=B6nig?= Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This is something that we've wanted for a while now: the ability to actually look up the respective drm_device for a given drm_dp_aux struct. This will also allow us to transition over to using the drm_dbg_*() helpers for debug message printing, as we'll finally have a drm_device to reference for doing so. Note that there is one limitation with this - because some DP AUX adapters exist as platform devices which are initialized independently of their respective DRM devices, one cannot rely on drm_dp_aux->drm_dev to always be non-NULL until drm_dp_aux_register() has been called. We make sure to point this out in the documentation for struct drm_dp_aux. v3: * Add WARN_ON_ONCE() to drm_dp_aux_register() if drm_dev isn't filled out Signed-off-by: Lyude Paul Acked-by: Thierry Reding --- drivers/gpu/drm/amd/amdgpu/atombios_dp.c | 7 ++++--- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 1 + drivers/gpu/drm/bridge/analogix/analogix-anx6345.c | 1 + drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c | 1 + drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 1 + drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 1 + drivers/gpu/drm/bridge/tc358767.c | 1 + drivers/gpu/drm/bridge/ti-sn65dsi86.c | 1 + drivers/gpu/drm/drm_dp_aux_dev.c | 6 ++++++ drivers/gpu/drm/drm_dp_helper.c | 2 ++ drivers/gpu/drm/drm_dp_mst_topology.c | 1 + drivers/gpu/drm/i915/display/intel_dp_aux.c | 1 + drivers/gpu/drm/msm/edp/edp.h | 3 +-- drivers/gpu/drm/msm/edp/edp_aux.c | 5 +++-- drivers/gpu/drm/msm/edp/edp_ctrl.c | 2 +- drivers/gpu/drm/nouveau/nouveau_connector.c | 1 + drivers/gpu/drm/radeon/atombios_dp.c | 1 + drivers/gpu/drm/tegra/dpaux.c | 1 + drivers/gpu/drm/xlnx/zynqmp_dp.c | 1 + include/drm/drm_dp_helper.h | 9 ++++++++- 20 files changed, 38 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c index 54c209ab8c9f..14a097322238 100644 --- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c +++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c @@ -190,11 +190,12 @@ int amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector) amdgpu_connector->ddc_bus->rec.hpd = amdgpu_connector->hpd.hpd; amdgpu_connector->ddc_bus->aux.transfer = amdgpu_atombios_dp_aux_transfer; + amdgpu_connector->ddc_bus->aux.drm_dev = amdgpu_connector->base.dev; + ret = drm_dp_aux_init(&amdgpu_connector->ddc_bus->aux); - if (ret) - return ret; + if (!ret) + amdgpu_connector->ddc_bus->has_aux = true; - amdgpu_connector->ddc_bus->has_aux = true; return ret; } diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 51fbbf3ef59b..a98bd3b521b2 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -438,6 +438,7 @@ int amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm, dm_aux->aux.transfer = dm_dp_aux_transfer; dm_aux->ddc_service = aconnector->dc_link->ddc; + dm_aux->aux.drm_dev = dm->ddev; ret = drm_dp_aux_init(&dm_aux->aux); if (ret) diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c index c105dcb79c37..f4e6a53f3821 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c @@ -537,6 +537,7 @@ static int anx6345_bridge_attach(struct drm_bridge *bridge, /* Register aux channel */ anx6345->aux.name = "DP-AUX"; anx6345->aux.dev = &anx6345->client->dev; + anx6345->aux.drm_dev = bridge->dev; anx6345->aux.transfer = anx6345_aux_transfer; err = drm_dp_aux_register(&anx6345->aux); diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c index 0778458e81be..7bd28c077181 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c @@ -905,6 +905,7 @@ static int anx78xx_bridge_attach(struct drm_bridge *bridge, /* Register aux channel */ anx78xx->aux.name = "DP-AUX"; anx78xx->aux.dev = &anx78xx->client->dev; + anx78xx->aux.drm_dev = bridge->dev; anx78xx->aux.transfer = anx78xx_aux_transfer; err = drm_dp_aux_register(&anx78xx->aux); diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index f82e193d32ae..17359bb7a82d 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1765,6 +1765,7 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev) dp->aux.name = "DP-AUX"; dp->aux.transfer = analogix_dpaux_transfer; dp->aux.dev = dp->dev; + dp->aux.drm_dev = drm_dev; ret = drm_dp_aux_register(&dp->aux); if (ret) diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c index 518e9a441c21..72ace172e0e9 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c @@ -1719,6 +1719,7 @@ static int cdns_mhdp_attach(struct drm_bridge *bridge, dev_dbg(mhdp->dev, "%s\n", __func__); + mhdp->aux.drm_dev = bridge->dev; ret = drm_dp_aux_register(&mhdp->aux); if (ret < 0) return ret; diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 6a56acf36a9a..9c8e8be2a088 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -1414,6 +1414,7 @@ static int tc_bridge_attach(struct drm_bridge *bridge, if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) return 0; + tc->aux.drm_dev = drm; ret = drm_dp_aux_register(&tc->aux); if (ret < 0) return ret; diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 6190451c9195..6245dfaf6fd7 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -362,6 +362,7 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge, return -EINVAL; } + pdata->aux.drm_dev = bridge->dev; ret = drm_dp_aux_register(&pdata->aux); if (ret < 0) { drm_err(bridge->dev, "Failed to register DP AUX channel: %d\n", ret); diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c index e25181bf2c48..06b374cae956 100644 --- a/drivers/gpu/drm/drm_dp_aux_dev.c +++ b/drivers/gpu/drm/drm_dp_aux_dev.c @@ -278,6 +278,12 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux) if (!aux_dev) /* attach must have failed */ return; + /* + * As some AUX adapters may exist as platform devices which outlive their respective DRM + * devices, we clear drm_dev to ensure that we never accidentally reference a stale pointer + */ + aux->drm_dev = NULL; + mutex_lock(&aux_idr_mutex); idr_remove(&aux_idr, aux_dev->index); mutex_unlock(&aux_idr_mutex); diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 6c9e552233fd..b34105c41867 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -1815,6 +1815,8 @@ int drm_dp_aux_register(struct drm_dp_aux *aux) int ret; const bool init_aux = !aux->ddc.algo; + WARN_ON_ONCE(!aux->drm_dev); + if (init_aux) { ret = drm_dp_aux_init(aux); if (ret) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 159014455fab..276f7f054d62 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2350,6 +2350,7 @@ drm_dp_mst_add_port(struct drm_device *dev, port->aux.is_remote = true; /* initialize the MST downstream port's AUX crc work queue */ + port->aux.drm_dev = dev; drm_dp_remote_aux_init(&port->aux); /* diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c index a79c6e781638..ac6f697c1862 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c @@ -684,6 +684,7 @@ int intel_dp_aux_init(struct intel_dp *intel_dp) else intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl; + intel_dp->aux.drm_dev = &dev_priv->drm; ret = drm_dp_aux_init(&intel_dp->aux); if (ret) return ret; diff --git a/drivers/gpu/drm/msm/edp/edp.h b/drivers/gpu/drm/msm/edp/edp.h index eb34243dad53..8590f2ce274d 100644 --- a/drivers/gpu/drm/msm/edp/edp.h +++ b/drivers/gpu/drm/msm/edp/edp.h @@ -46,8 +46,7 @@ void edp_bridge_destroy(struct drm_bridge *bridge); struct drm_connector *msm_edp_connector_init(struct msm_edp *edp); /* AUX */ -void *msm_edp_aux_init(struct device *dev, void __iomem *regbase, - struct drm_dp_aux **drm_aux); +void *msm_edp_aux_init(struct msm_edp *edp, void __iomem *regbase, struct drm_dp_aux **drm_aux); void msm_edp_aux_destroy(struct device *dev, struct edp_aux *aux); irqreturn_t msm_edp_aux_irq(struct edp_aux *aux, u32 isr); void msm_edp_aux_ctrl(struct edp_aux *aux, int enable); diff --git a/drivers/gpu/drm/msm/edp/edp_aux.c b/drivers/gpu/drm/msm/edp/edp_aux.c index ced3a38781ed..1a48084c9bdc 100644 --- a/drivers/gpu/drm/msm/edp/edp_aux.c +++ b/drivers/gpu/drm/msm/edp/edp_aux.c @@ -184,9 +184,9 @@ static ssize_t edp_aux_transfer(struct drm_dp_aux *drm_aux, return ret; } -void *msm_edp_aux_init(struct device *dev, void __iomem *regbase, - struct drm_dp_aux **drm_aux) +void *msm_edp_aux_init(struct msm_edp *edp, void __iomem *regbase, struct drm_dp_aux **drm_aux) { + struct device *dev = &edp->pdev->dev; struct edp_aux *aux = NULL; int ret; @@ -201,6 +201,7 @@ void *msm_edp_aux_init(struct device *dev, void __iomem *regbase, aux->drm_aux.name = "msm_edp_aux"; aux->drm_aux.dev = dev; + aux->drm_aux.drm_dev = edp->dev; aux->drm_aux.transfer = edp_aux_transfer; ret = drm_dp_aux_register(&aux->drm_aux); if (ret) { diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c index 0d9657cc70db..57af3d8b6699 100644 --- a/drivers/gpu/drm/msm/edp/edp_ctrl.c +++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c @@ -1153,7 +1153,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp) } /* Init aux and phy */ - ctrl->aux = msm_edp_aux_init(dev, ctrl->base, &ctrl->drm_aux); + ctrl->aux = msm_edp_aux_init(edp, ctrl->base, &ctrl->drm_aux); if (!ctrl->aux || !ctrl->drm_aux) { pr_err("%s:failed to init aux\n", __func__); return -ENOMEM; diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 56eaa29b34d6..b4cefb0a34d0 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -1355,6 +1355,7 @@ nouveau_connector_create(struct drm_device *dev, case DRM_MODE_CONNECTOR_DisplayPort: case DRM_MODE_CONNECTOR_eDP: nv_connector->aux.dev = connector->kdev; + nv_connector->aux.drm_dev = dev; nv_connector->aux.transfer = nouveau_connector_aux_xfer; snprintf(aux_name, sizeof(aux_name), "sor-%04x-%04x", dcbe->hasht, dcbe->hashm); diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 15b00a347560..c50c504bad50 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -232,6 +232,7 @@ void radeon_dp_aux_init(struct radeon_connector *radeon_connector) radeon_connector->ddc_bus->rec.hpd = radeon_connector->hpd.hpd; radeon_connector->ddc_bus->aux.dev = radeon_connector->base.kdev; + radeon_connector->ddc_bus->aux.drm_dev = radeon_connector->base.dev; if (ASIC_IS_DCE5(rdev)) { if (radeon_auxch) radeon_connector->ddc_bus->aux.transfer = radeon_dp_aux_transfer_native; diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c index 6379f2f32d4d..84a4c46c201d 100644 --- a/drivers/gpu/drm/tegra/dpaux.c +++ b/drivers/gpu/drm/tegra/dpaux.c @@ -727,6 +727,7 @@ int drm_dp_aux_attach(struct drm_dp_aux *aux, struct tegra_output *output) unsigned long timeout; int err; + aux->drm_dev = output->connector.dev; err = drm_dp_aux_register(aux); if (err < 0) return err; diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c index 5370b99aabdf..e8efbab5ae69 100644 --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c @@ -1069,6 +1069,7 @@ static int zynqmp_dp_aux_init(struct zynqmp_dp *dp) dp->aux.name = "ZynqMP DP AUX"; dp->aux.dev = dp->dev; + dp->aux.drm_dev = dp->drm; dp->aux.transfer = zynqmp_dp_aux_transfer; return drm_dp_aux_register(&dp->aux); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 54d13a4d819f..417b2c101a1e 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1840,6 +1840,8 @@ struct drm_dp_aux_cec { * @name: user-visible name of this AUX channel and the I2C-over-AUX adapter * @ddc: I2C adapter that can be used for I2C-over-AUX communication * @dev: pointer to struct device that is the parent for this AUX channel + * @drm_dev: pointer to the &drm_device that owns this AUX channel. Beware, this may be %NULL + * before drm_dp_aux_register() has been called. * @crtc: backpointer to the crtc that is currently using this AUX channel * @hw_mutex: internal mutex used for locking transfers * @crc_work: worker that captures CRCs for each frame @@ -1847,7 +1849,11 @@ struct drm_dp_aux_cec { * @transfer: transfers a message representing a single AUX transaction * * The @dev field should be set to a pointer to the device that implements the - * AUX channel. + * AUX channel. As well, the @drm_dev field should be set to the &drm_device + * that will be using this AUX channel as early as possible. For many graphics + * drivers this should happen before drm_dp_aux_init(), however it's perfectly + * fine to set this field later so long as it's assigned before calling + * drm_dp_aux_register(). * * The @name field may be used to specify the name of the I2C adapter. If set to * %NULL, dev_name() of @dev will be used. @@ -1879,6 +1885,7 @@ struct drm_dp_aux { const char *name; struct i2c_adapter ddc; struct device *dev; + struct drm_device *drm_dev; struct drm_crtc *crtc; struct mutex hw_mutex; struct work_struct crc_work;