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 3AAF93491D5 for ; Fri, 21 Nov 2025 12:07:44 +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=1763726867; cv=none; b=pu6mtkQYhxgLOZ3v5rSR+H22op7dND8Trh6ihYMBCN5x47T1dADYe9ox921czDSmGk6n9FfTxywC12P8spcelO1OFGvoBlswHzwwQMa2jj9g1c0dOQJwq9hmdS3TKz/Zu0YrNnRhAXqEtJcqmQ+dlPFxvgB9WxOMzh1TJyXmiK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763726867; c=relaxed/simple; bh=CSz7DcU4vC7vNNXvv0S58mDvdmc6kNxg9oj2/N9Le9w=; h=Message-ID:Date:MIME-Version:Subject:To:References:From:Cc: In-Reply-To:Content-Type; b=hAOQCbKchnpRDd8Ms0gvIqjjdmoZbcTn0r7Yregoiors7LDIxbVUFKvUzoTMwaVljjZu/y1MIEiedzPzZeqJ3V4sWKqsa7Y4SNvRQLmFRmHr0MLfPMhPcW3yISEhphMKgainLJGyxAdrUucmzZDBiSa0Ro49SxJS03TRsLBgVMs= 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=r3gfstet; 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="r3gfstet" 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 21C836A6; Fri, 21 Nov 2025 13:05:33 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1763726735; bh=CSz7DcU4vC7vNNXvv0S58mDvdmc6kNxg9oj2/N9Le9w=; h=Date:Subject:To:References:From:Cc:In-Reply-To:From; b=r3gfstetiWyxxWsWJLuaKMQ9+9p/YTqnYLcM8ayzbl/6E5VzSm8aUnjTIPaG0Lexv cOKWkxiYEH6ew1uqyQsVVSKe19jv2HotgCFeFEuqybsBenH9sVjUwshke8i19zBTVh yrWC4scl8vEQhpxTltQwMeyNF6x+4o4hfqMxOWq8= Message-ID: <22985633-f20c-4f36-96d1-ce01fe6cf6df@ideasonboard.com> Date: Fri, 21 Nov 2025 14:07:36 +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 0/6] MHDP8546 fixes related to DRM_BRIDGE_ATTACH_NO_CONNECTOR usecase To: Harikrishna Shenoy References: <20251120121416.660781-1-h-shenoy@ti.com> From: Tomi Valkeinen Content-Language: en-US Cc: Laurent.pinchart@ideasonboard.com, airlied@gmail.com, andrzej.hajda@intel.com, andy.yan@rock-chips.com, aradhya.bhatia@linux.dev, devarsht@ti.com, dianders@chromium.org, dri-devel@lists.freedesktop.org, javierm@redhat.com, jernej.skrabec@gmail.com, jonas@kwiboo.se, linux-kernel@vger.kernel.org, linux@treblig.org, luca.ceresoli@bootlin.com, lumag@kernel.org, lyude@redhat.com, maarten.lankhorst@linux.intel.com, mordan@ispras.ru, mripard@kernel.org, neil.armstrong@linaro.org, rfoss@kernel.org, s-jain1@ti.com, simona@ffwll.ch, tzimmermann@suse.de, u-kumar1@ti.com 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: > With the DRM_BRIDGE_ATTACH_NO_CONNECTOR framework, the connector is > no longer initialized in bridge_attach() when the display controller > sets the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag. > This causes a null pointer dereference in cdns_mhdp_modeset_retry_fn() > when trying to access &conn->dev->mode_config.mutex. > Observed on a board where EDID read failed. > (log: https://gist.github.com/Jayesh2000/233f87f9becdf1e66f1da6fd53f77429) > > Patch 1 adds a connector_ptr which takes care of both > DRM_BRIDGE_ATTACH_NO_CONNECTOR and !DRM_BRIDGE_ATTACH_NO_CONNECTOR > case by setting the pointer in appropriate hooks and checking for pointer > validity before accessing the connector. > Patch 2 adds mode validation hook to bridge fucntions. > Patch 3 fixes HDCP to work with both DRM_BRIDGE_ATTACH_NO_CONNECTOR > and !DRM_BRIDGE_ATTACH_NO_CONNECTOR case by moving HDCP state handling > into the bridge atomic check inline with the > DRM_BRIDGE_ATTACH_NO_CONNECTOR model. > Patches 4,5 do necessary cleanup and alignment for using > connector pointer. > > The rationale behind the sequence of commits is we can cleanly > switch to drm_connector pointer after removal of connector helper > code blocks, which are anyways not touch after > DRM_BRIDGE_ATTACH_NO_CONNECTOR has been enabled in driver. > > The last patch make smaller adjustment: lowering the log level for > noisy DPCD transfer errors. > > v8 patch link: > > > Changelog v8-v9: > -Move the patch 6 in v8 related to HDCP to patch 3 and add fixes tag. > -Update to connector_ptr in HDCP code in patch 1. > -Rebased on next-20251114. Don't base on linux-next, except in some quite special circumstances. Base on latest major version from Linus, or -rc from Linus, or drm-misc-next. Usually drm-misc-next is a safe choice for DRM patches. And if you make changes to a series, it's not a "resend" but a new version. Tomi > > v7 patch link: > > > Changelog v7-v8: > -Move patches with firxes tag to top of series with appropriate changes > to them. > -Add R/B tag to patch > https://lore.kernel.org/all/ae3snoap64r252sbqhsshsadxfmlqdfn6b4o5fgfcmxppglkqf@2lsstfsghzwb/ > > v6 patch link: > > > Changelog v6-v7: > -Update cover letter to explain the series. > -Add R/B tag in PATCH 1 and drop fixes tag as suggested. > -Drop fixes tag in PATCH 2. > -Update the commit messages for clear understanding of changes done in patches. > > v5 patch link: > > > Changelog v5 -> v6: > -Update cover letter to clarify the series in better way. > -Add Reviewed-by tag to relevant patches. > > v4 patch link: > > > Changelog v4->v5: > - Handle HDCP state in bridge atomic check instead of connector > atomic check > > v3 patch link: > > > Changelog v3->v4: > - Fix kernel test robot build warning: > > > v2 patch link: > > > Changelog v2->v3: > - Add mode_valid in drm_bridge_funcs to a separate patch > - Remove "if (mhdp->connector.dev)" conditions that were missed in v2 > - Split out the move of drm_atomic_get_new_connector_for_encoder() > to a separate patch > - Drop "R-by" considering the changes in v2[1/3] > - Add Fixes tag to first 4 patches: > commit c932ced6b585 ("drm/tidss: Update encoder/bridge chain connect model") > This added DBANC flag in tidss while attaching bridge to the encoder > - Drop RFC prefix > > v1 patch link: > > > Changelog v1->v2: > - Remove !DRM_BRIDGE_ATTACH_NO_CONNECTOR entirely > - Add mode_valid in drm_bridge_funcs[0] > - Fix NULL POINTER differently since we cannot access atomic_state > - Reduce log level in cdns_mhdp_transfer call > > [0]: https://lore.kernel.org/all/20240530091757.433106-1-j-choudhary@ti.com/ > > Harikrishna Shenoy (1): > drm/bridge: cadence: cdns-mhdp8546-core: Handle HDCP state in bridge > atomic check > > Jayesh Choudhary (5): > drm/bridge: cadence: cdns-mhdp8546-core: Set the mhdp connector > earlier in atomic_enable() > drm/bridge: cadence: cdns-mhdp8546-core: Add mode_valid hook to > drm_bridge_funcs > drm/bridge: cadence: cdns-mhdp8546-core: Remove legacy support for > connector initialisation in bridge > drm/bridge: cadence: cdns-mhdp8546*: Change drm_connector from > structure to pointer > drm/bridge: cadence: cdns-mhdp8546-core: Reduce log level for DPCD > read/write > > .../drm/bridge/cadence/cdns-mhdp8546-core.c | 258 +++++------------- > .../drm/bridge/cadence/cdns-mhdp8546-core.h | 2 +- > .../drm/bridge/cadence/cdns-mhdp8546-hdcp.c | 8 +- > 3 files changed, 72 insertions(+), 196 deletions(-) >