From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 C86AE8004B for ; Wed, 6 Mar 2024 16:30:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709742620; cv=none; b=FrDFTGeIieFUHBbCZ0filXiIkEuDNzuFCaXveyYY2c2QMTIpxDTl0ICs8qd1/OkYDNUHZHRLQZR4z/bTglxInl0KlTYkqAJ8lA1x2yY5yg26/tpFQhsnEbJ3xKVcpFE0xdXzev7hHtt4jpUEId51gBjWMNzDXAJYvWfooYrcLQs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709742620; c=relaxed/simple; bh=ZX+x8Loog5/ZauzAzuqgUjmagbLEgPQfhcH7oa7WCyE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pwRQdnqaY0yZEpffsmxOWFqVRWBZmr8ySUligF/hbbytW4wHcSYAcTfyCxDB3XV9A7QLORkLpv78m1FBoGwPIhpmm/glfXMtwygAf27etYfw2UAcMi9lWlFYcNLdJGhv2QqVwxOSnS0QLjrtUXTL4SOSLSjXjhd16yS49hx7TcY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=fbX843BV; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="fbX843BV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1709742619; x=1741278619; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ZX+x8Loog5/ZauzAzuqgUjmagbLEgPQfhcH7oa7WCyE=; b=fbX843BV4l1mNd8sundoDXpfMTX8LfVNa2p6bdLBA4T/a2r1DNxl+Z3K YoHjGifqg9DA1gWebd2paFQlMcjfpduFCzuk97d6/S7EyHGNWEtJ+k0Yl 3S7CwP1ElPylDKzxdAwPK8YUMQjI6+6Q+VXmJERMVT4Iz7Hydil3nPTLT YlMgK1kKXFEM8+9B9FMiG8E+NUFbOb0sEXuxNpf6dBy+i1g14xqld3YKR B4CraFp3GtLCzoREzzQyP0KzoAKRRb9bfnplTpjDoUpSzwyNHGIck8ZbT 5GcVMO9BBpaPaOZb4e5/34uKx7nIYsMrfyycvMGLmEs6Q5YMJyyE39hF5 w==; X-IronPort-AV: E=McAfee;i="6600,9927,11005"; a="4251363" X-IronPort-AV: E=Sophos;i="6.06,208,1705392000"; d="scan'208";a="4251363" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2024 08:30:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,208,1705392000"; d="scan'208";a="9673743" Received: from pmatthew-mobl2.amr.corp.intel.com (HELO [10.213.169.105]) ([10.213.169.105]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2024 08:30:17 -0800 Message-ID: Date: Wed, 6 Mar 2024 10:30:16 -0600 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 1/4] ACPI: NHLT: Reintroduce types the table consists of Content-Language: en-US To: Cezary Rojewski , Andy Shevchenko Cc: rafael@kernel.org, linux-acpi@vger.kernel.org, robert.moore@intel.com, amadeuszx.slawinski@linux.intel.com References: <20240304161335.1734134-1-cezary.rojewski@intel.com> <20240304161335.1734134-2-cezary.rojewski@intel.com> <0d1b777e-bd95-4755-8e4c-ee37640d155b@linux.intel.com> <17d55fd0-8884-4f05-99f7-abccdda0e174@linux.intel.com> <312ff9d7-8b90-428f-b90c-ebb278e029a7@intel.com> <5b615397-2c9e-44cb-8f2f-6f763f0643e9@intel.com> From: Pierre-Louis Bossart In-Reply-To: <5b615397-2c9e-44cb-8f2f-6f763f0643e9@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 3/6/24 10:17, Cezary Rojewski wrote: > On 2024-03-04 9:46 PM, Pierre-Louis Bossart wrote: >> On 3/4/24 14:34, Cezary Rojewski wrote: >>> On 2024-03-04 9:22 PM, Pierre-Louis Bossart wrote: >>>> On 3/4/24 13:49, Andy Shevchenko wrote: >>>>> On Mon, Mar 04, 2024 at 10:57:39AM -0600, Pierre-Louis Bossart wrote: >>>>>>> +/* Values for link_type field above */ >>>>>>> + >>>>>>> +#define ACPI_NHLT_LINKTYPE_HDA            0 >>>>>>> +#define ACPI_NHLT_LINKTYPE_DSP            1 >>>>>>> +#define ACPI_NHLT_LINKTYPE_PDM            2 >>>>>>> +#define ACPI_NHLT_LINKTYPE_SSP            3 >>>>>>> +#define ACPI_NHLT_LINKTYPE_SLIMBUS        4 >>>>>>> +#define ACPI_NHLT_LINKTYPE_SDW            5 >>>>>>> +#define ACPI_NHLT_LINKTYPE_UAOL            6 >>>>>> >>>>>> More than half of those values are not used. Is there really any >>>>>> benefit >>>>>> in exposing them? >>>>> >>>>> Sometimes a code is the (only) documentation. Since it's a global >>>>> header and >>>>> part of ACPICA we probably better to expose all bits that are defined. >>>> >>>> NHLT is an Intel-only solution - no other company uses it. >>>> Intel does not have any designs where SlimBus is productized. >>>> >>>> I fail to see the wisdom of exposing a non-existent option with >>>> LINKTYPE_SLIMBUS. It's not because this case was listed in a document >>>> that we have to add the information verbatim in a open-source header. >>>> >>>> Likewise for SoundWire we do NOT use NHLT at all... >>>> >>>> Options 4 and 5 are completely irrelevant. 0 and 1 most likely as well. >>> >>> Hello, >>> >>> How relevant or not given field is in LINKTYPE enumeration is.. >>> irrelevant. Those values are reserved since the dawn of the table. >>> Renaming those with range of RESERVED_X(s) is hardly an alternative. On >>> top of that, specs which have been publicly shared since 2016 _do_ list >>> the non-I2S/PDW constants when describing LINKTYPE. >> >> I maintain that all those values, while spec-defined, should be treated >> as not supported. It's not unusual in engineering to change directions >> and back-annotate, demote or cleanup initial designs. Change is the only >> constant. > > What's the proposal here? Would comment suffice or there is something > else you have in mind? I would be fine with a comment along the lines of 'defined in spec, not used' and 'used on all SKL+ platforms'.