From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CA7A25B663 for ; Fri, 21 Nov 2025 12:41:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763728893; cv=none; b=I5jASV9tRTPQWa4PcnlkMXnV8rxp8UMVirznOx1IIyyiS63YoEwuMmQRYX7lhRTnmDlSrLnJYgA+4rEu/3FxCg8//V71SZAQhfmiRPIzSQctMCmeeNaU7SY4tSikC2w+Bbu/+5Cbj1/t+scaDKAruRg1uZzBREoybsY11mJUzDA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763728893; c=relaxed/simple; bh=9pxOOkdPGNk3BYE1sjuMuMtQKUrlSJNjPfbZriHAvMg=; h=Message-ID:Date:MIME-Version:Subject:To:References:From:Cc: In-Reply-To:Content-Type; b=apsrHM4HOgWSqC2klTRWNlONSsbZbfXa83q5qyDHMn/j7QkBBewOTVayncY0OaKLCz9fVTNwTFIfFn+EF4JeH7VHZFMbGS2vJuxWfiFxlOOwBsjXGe5K4MNRisQNaC2BEh9daVapdo29aJjegPqKQS2aygff2ZYXXjTwGjyVOLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=aKdVioPd; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="aKdVioPd" Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E6DA56A6; Fri, 21 Nov 2025 13:39:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1763728762; bh=9pxOOkdPGNk3BYE1sjuMuMtQKUrlSJNjPfbZriHAvMg=; h=Date:Subject:To:References:From:Cc:In-Reply-To:From; b=aKdVioPdOysFlTr6Mc2h8+Wy5UBE7HNf138W1lUmG2IxQklBdU/KQEI5wI6JBN/vI +TnOoT3VALSvTb9aY60LHKfonkDVBZgr8f/wKwmKStq01OErzUqhiht3tN8HMranAa UCnVYP+bGyZnnM9HApTk85c43nuHaXBXwdZzetZ0= Message-ID: <9a041a93-c004-40a9-b94e-ae3fce339145@ideasonboard.com> Date: Fri, 21 Nov 2025 14:41:23 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND v9 1/6] drm/bridge: cadence: cdns-mhdp8546-core: Set the mhdp connector earlier in atomic_enable() To: Harikrishna Shenoy References: <20251120121416.660781-1-h-shenoy@ti.com> <20251120121416.660781-2-h-shenoy@ti.com> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 20/11/2025 14:14, Harikrishna Shenoy wrote: > From: Jayesh Choudhary > > In case if we get errors in cdns_mhdp_link_up() or cdns_mhdp_reg_read() > in atomic_enable, we will go to cdns_mhdp_modeset_retry_fn() and will hit > NULL pointer while trying to access the mutex. We need the connector to > be set before that. Unlike in legacy cases with flag > !DRM_BRIDGE_ATTACH_NO_CONNECTOR, we do not have connector initialised > in bridge_attach(), so add the mhdp->connector_ptr in device structure > to handle both cases with DRM_BRIDGE_ATTACH_NO_CONNECTOR and > !DRM_BRIDGE_ATTACH_NO_CONNECTOR, set it in atomic_enable() earlier to > avoid possible NULL pointer dereference in recovery paths like > modeset_retry_fn() with the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag set. > > Fixes: c932ced6b585 ("drm/tidss: Update encoder/bridge chain connect model") > Signed-off-by: Jayesh Choudhary > Signed-off-by: Harikrishna Shenoy > --- > .../drm/bridge/cadence/cdns-mhdp8546-core.c | 29 ++++++++++--------- > .../drm/bridge/cadence/cdns-mhdp8546-core.h | 1 + > .../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 26 ++++++++++++----- > 3 files changed, 34 insertions(+), 22 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > index 38726ae1bf150..f3076e9cdabbe 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > @@ -740,7 +740,7 @@ static void cdns_mhdp_fw_cb(const struct firmware *fw, void *context) > bridge_attached = mhdp->bridge_attached; > spin_unlock(&mhdp->start_lock); > if (bridge_attached) { > - if (mhdp->connector.dev) > + if (mhdp->connector_ptr && mhdp->connector_ptr->dev) > drm_kms_helper_hotplug_event(mhdp->bridge.dev); > else > drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp)); > @@ -1636,6 +1636,7 @@ static int cdns_mhdp_connector_init(struct cdns_mhdp_device *mhdp) > return ret; > } > > + mhdp->connector_ptr = conn; > drm_connector_helper_add(conn, &cdns_mhdp_conn_helper_funcs); > > ret = drm_display_info_set_bus_formats(&conn->display_info, > @@ -1915,17 +1916,25 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge, > struct cdns_mhdp_device *mhdp = bridge_to_mhdp(bridge); > struct cdns_mhdp_bridge_state *mhdp_state; > struct drm_crtc_state *crtc_state; > - struct drm_connector *connector; > struct drm_connector_state *conn_state; > struct drm_bridge_state *new_state; > const struct drm_display_mode *mode; > u32 resp; > - int ret; > + int ret = 0; > > dev_dbg(mhdp->dev, "bridge enable\n"); > > mutex_lock(&mhdp->link_mutex); > > + mhdp->connector_ptr = drm_atomic_get_new_connector_for_encoder(state, > + bridge->encoder); > + if (WARN_ON(!mhdp->connector_ptr)) > + goto out; > + > + conn_state = drm_atomic_get_new_connector_state(state, mhdp->connector_ptr); > + if (WARN_ON(!conn_state)) > + goto out; > + > if (mhdp->plugged && !mhdp->link_up) { > ret = cdns_mhdp_link_up(mhdp); > if (ret < 0) > @@ -1945,15 +1954,6 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge, > cdns_mhdp_reg_write(mhdp, CDNS_DPTX_CAR, > resp | CDNS_VIF_CLK_EN | CDNS_VIF_CLK_RSTN); > > - connector = drm_atomic_get_new_connector_for_encoder(state, > - bridge->encoder); > - if (WARN_ON(!connector)) > - goto out; > - > - conn_state = drm_atomic_get_new_connector_state(state, connector); > - if (WARN_ON(!conn_state)) > - goto out; > - > if (mhdp->hdcp_supported && > mhdp->hw_state == MHDP_HW_READY && > conn_state->content_protection == > @@ -2030,6 +2030,7 @@ static void cdns_mhdp_atomic_disable(struct drm_bridge *bridge, > if (mhdp->info && mhdp->info->ops && mhdp->info->ops->disable) > mhdp->info->ops->disable(mhdp); > > + mhdp->connector_ptr = NULL; > mutex_unlock(&mhdp->link_mutex); > } > > @@ -2296,7 +2297,7 @@ static void cdns_mhdp_modeset_retry_fn(struct work_struct *work) > > mhdp = container_of(work, typeof(*mhdp), modeset_retry_work); > > - conn = &mhdp->connector; > + conn = mhdp->connector_ptr; > > /* Grab the locks before changing connector property */ > mutex_lock(&conn->dev->mode_config.mutex); > @@ -2373,7 +2374,7 @@ static void cdns_mhdp_hpd_work(struct work_struct *work) > int ret; > > ret = cdns_mhdp_update_link_status(mhdp); > - if (mhdp->connector.dev) { > + if (mhdp->connector_ptr && mhdp->connector_ptr->dev) { > if (ret < 0) > schedule_work(&mhdp->modeset_retry_work); > else > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > index bad2fc0c73066..a76775c768956 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h > @@ -376,6 +376,7 @@ struct cdns_mhdp_device { > struct mutex link_mutex; > > struct drm_connector connector; > + struct drm_connector *connector_ptr; > struct drm_bridge bridge; > > struct cdns_mhdp_link link; > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c > index 42248f179b69d..5ac2fad2f0078 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c > @@ -393,8 +393,10 @@ static int _cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp) > { > int ret; > > - dev_dbg(mhdp->dev, "[%s:%d] HDCP is being disabled...\n", > - mhdp->connector.name, mhdp->connector.base.id); > + if (mhdp->connector_ptr) { > + dev_dbg(mhdp->dev, "[%s:%d] HDCP is being disabled...\n", > + mhdp->connector_ptr->name, mhdp->connector_ptr->base.id); > + } > > ret = cdns_mhdp_hdcp_set_config(mhdp, 0, false); > > @@ -443,9 +445,11 @@ static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp) > if (!ret && hdcp_port_status & HDCP_PORT_STS_AUTH) > goto out; > > - dev_err(mhdp->dev, > - "[%s:%d] HDCP link failed, retrying authentication\n", > - mhdp->connector.name, mhdp->connector.base.id); > + if (mhdp->connector_ptr) { > + dev_err(mhdp->dev, > + "[%s:%d] HDCP link failed, retrying authentication\n", > + mhdp->connector_ptr->name, mhdp->connector_ptr->base.id); > + } This looks hackish... What's the point of printing the connector name and id anyway? For MST? And if we don't have a connector, is there any point in doing anything in cdns_mhdp_hdcp_check_link() or the other functions that have similar prints? Or why would they even be called? Are they ever called if we don't have a connector? I think for now, it's simplest to just drop the use of connector_ptr from the prints, instead of these odd if()s. Or assume that we do have connector_ptr, if the driver is designed that way. > > ret = _cdns_mhdp_hdcp_disable(mhdp); > if (ret) { > @@ -487,13 +491,19 @@ static void cdns_mhdp_hdcp_prop_work(struct work_struct *work) > struct cdns_mhdp_device *mhdp = container_of(hdcp, > struct cdns_mhdp_device, > hdcp); > - struct drm_device *dev = mhdp->connector.dev; > + struct drm_device *dev = NULL; > struct drm_connector_state *state; > > + if (mhdp->connector_ptr) > + dev = mhdp->connector_ptr->dev; > + > + if (!dev) > + return; > + > drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); > mutex_lock(&mhdp->hdcp.mutex); > - if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) { > - state = mhdp->connector.state; > + if (mhdp->connector_ptr && mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) { Earlier in the function you check if there's a connector, and if not, dev is NULL, and there's return. So the code can never reach here if connector_ptr is NULL. > + state = mhdp->connector_ptr->state; > state->content_protection = mhdp->hdcp.value; The only real thing this function does are the two lines above. So I think you can just : if (!mhdp->connector_ptr || !mhdp->connector_ptr->dev) return; (or something similar) at the beginning of the function. Or should it be inside the connection_mutex, this one is a scheduled work... Tomi > } > mutex_unlock(&mhdp->hdcp.mutex);