From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 0FE6C2882C0 for ; Tue, 27 May 2025 19:24:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748373879; cv=none; b=V4c3D98mwkFEdn6WxvOmECjFIh78xwWwLF254lqlfrPne7WiTzlGcTIt+s9SVAsmWRfUHjjnuG/5A9kZ7iJ3fDymwHMgiaLHOUHCaO2ZshnDME0YKepvuZ6/nUms5Y9+vwvYHA+vCRF7pZCTm+k8GwejEFTc3tyQ/MKG1rrP8XM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748373879; c=relaxed/simple; bh=ntw/8psZ7bfxneDfhhEexKAZ6oulFJnYo89SZiJwBzs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=V/KVmqCJKipkVTovTbdDVqDh5qQB+lm8+x84R1xLYc30tATdYNk35KCEox4Bsfb8D01tdVPrgfWoh0Pp0rZvBmehnPCgBSA8KCq9chSa01V59Jj3tEbw5C8H5/1uoQaDCCL/AtAsF+Kj3l/uEQ8OjAl2jNCjtX+D1dtdG7/gAWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=YGRxpqux; arc=none smtp.client-ip=198.175.65.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="YGRxpqux" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1748373878; x=1779909878; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=ntw/8psZ7bfxneDfhhEexKAZ6oulFJnYo89SZiJwBzs=; b=YGRxpquxxOruR0fE+TfgoSk7ka5YcRjaFvBNNd2iiJTgeynkYg7X1Mj4 L6tX0kkENo6rhm3eLCKANfxA6exURXAgHcdnN+r2BRIbcFQg8O9qmb7o/ OGaW/Fa4ZCIuMDUwd1QldpcyW1+lvgTTrJIJqfguz+kUjF4mH6oS95EQo paiHhOTqs6Kfn/5HslroYx/W2Xwufy/qi+lZLkXX/2H6Ez8gCUQnNXpHM U/+he/mJx40vQN+jZVwqTBCz6NCbm5zhBsuwfi/GmlhEIMUDT70/J4KpE YQcpWJ3XCS7itTVUNmPqg/tcf1f7GxA/vuGQp7Xfl6z0ugNhRdf+cHyhy g==; X-CSE-ConnectionGUID: k2fAjVYdQoiu3GWGQbzKOQ== X-CSE-MsgGUID: SJQ7mBTNTUqjxiaaExYMMg== X-IronPort-AV: E=McAfee;i="6700,10204,11446"; a="50269201" X-IronPort-AV: E=Sophos;i="6.15,319,1739865600"; d="scan'208";a="50269201" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2025 12:24:38 -0700 X-CSE-ConnectionGUID: NeuleRm5T/qKTWvmmtRRLw== X-CSE-MsgGUID: 4eoINnEhQqaFaWdoQpz9Pg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,319,1739865600"; d="scan'208";a="142905777" Received: from smoticic-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.23]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2025 12:24:34 -0700 From: Jani Nikula To: Maxime Ripard Cc: Anusha Srivatsa , Neil Armstrong , Jessica Zhang , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Luca Ceresoli Subject: Re: [PATCH v4 2/4] drm/panel: Add refcount support In-Reply-To: <20250527-origami-mayfly-of-superiority-2a1cf1@houat> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20250505-slim-bizarre-marten-a674ac@houat> <874ixvtbxy.fsf@intel.com> <20250509-rapid-flounder-of-devotion-6b26bb@houat> <87r00yj6kv.fsf@intel.com> <875xi3im1r.fsf@intel.com> <20250519-singing-silent-stingray-fe5c9b@houat> <87sekztwyc.fsf@intel.com> <8210f7fc0dbcfc5b1eea47ccb762c7e53b45236a@intel.com> <20250527-origami-mayfly-of-superiority-2a1cf1@houat> Date: Tue, 27 May 2025 22:24:30 +0300 Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, 27 May 2025, Maxime Ripard wrote: > Hi, > > On Fri, May 23, 2025 at 02:34:05PM +0300, Jani Nikula wrote: >> On Tue, 20 May 2025, Jani Nikula wrote: >> > Maxime - >> > >> > I'm cutting a lot of context here. Not because I don't think it deserves >> > an answer, but because I seem to be failing at communication. >> > >> > On Mon, 19 May 2025, Maxime Ripard wrote: >> >> You still haven't explained why it would take anything more than >> >> registering a dumb device at probe time though. >> > >> > With that, do you mean a dumb struct device, or any struct device with a >> > suitable lifetime, that we'd pass to devm_drm_panel_alloc()? >> >> I'm no expert in ACPI, but I think it needs to be a struct device >> embedded inside struct acpi_device to implement the >> drm_panel_add_follower() lookup for ACPI. > > What data do you have in the ACPI tables to associate the HID > touchscreen to the panel? > > drm_panel_add_follower use the DT to lookup the panel, so the panel must > have a device->of_node pointer, so that obviously won't work, but it > might with ACPI, or we might need to split that function into several > parts to accomodate ACPI. Personally, I'm pretty clueless about ACPI, but apparently it's possible to add a _DSD to reference the panel. And something like [1] could work to make drm_panel lookup agnostic to DT/ACPI, but it's completely untested and unreviewed as of today. We'll also need to find someone to help ensure that doesn't break DT systems. Feedback is welcome, but please bear in mind I'm not even confident enough to post it on dri-devel yet. BR, Jani. [1] https://gitlab.freedesktop.org/jani/linux/-/commit/8ca2e1f25ca94c4ee094915a26781f9d9ace37af -- Jani Nikula, Intel