From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [RFC 00/10] Enable HDA Codec support on Intel Platforms (Series2) Date: Sun, 3 Dec 2017 21:44:56 -0600 Message-ID: References: <1512119648-2700-1-git-send-email-rakesh.a.ughreja@intel.com> <23319967-3571-9e8c-3077-94200bff813f@linux.intel.com> <20171203172037.GS32417@localhost> <780726ad-3587-1f05-89e4-800ad8ce7375@linux.intel.com> <20171204032229.GZ32417@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by alsa0.perex.cz (Postfix) with ESMTP id E1DED26710B for ; Mon, 4 Dec 2017 04:44:59 +0100 (CET) In-Reply-To: <20171204032229.GZ32417@localhost> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Vinod Koul Cc: alsa-devel@alsa-project.org, Takashi Iwai , liam.r.girdwood@linux.intel.com, patches.audio@intel.com, broonie@kernel.org, Rakesh Ughreja List-Id: alsa-devel@alsa-project.org On 12/3/17 9:22 PM, Vinod Koul wrote: > On Sun, Dec 03, 2017 at 09:15:21PM -0600, Pierre-Louis Bossart wrote: >> On 12/3/17 11:20 AM, Vinod Koul wrote: >>> On Fri, Dec 01, 2017 at 09:03:25PM +0100, Takashi Iwai wrote: >>>>>>> FIXME: >>>>>>> - KConfig changes does not look right, but I could not think of any proper >>>>>>> way without making changes into legacy HDA codec driver. So need some >>>>>>> help on this topic. >>>>>> >>>>>> And this is another big issue. As long as you don't allow build both, >>>>>> it never flies with distros, and it means no dramatic improvement of >>>>>> the situation, either. >>>>>> >>>>>> IOW, we have to make the codec driver working on both controller/bus >>>>>> implementations, and it essentially means to rewrite the HD-audio >>>>>> codec plumbing code. Currently, it's a kind of half-baked state, and >>>>>> we need to cast to unified form. >>>>> >>>>> Before going into codec support, should we first deal with the >>>>> selection of the ASoC/Legacy mode for the controller side of things? >>>>> Even with basic HDMI/iDisp cases, we don't have a clean solution >>>>> today. When I worked on the late Joule platform, there was no fallback >>>>> mode which forced a recompilation depending on BIOS settings. >>>>> My understanding is that there is no support for multiple drivers >>>>> registering for the same PCI ID, I believe we'll have to define a >>>>> top-level wrapper which arbitrates internally based on BIOS settings >>>>> and user/distro preferences which mode is selected. >>>> >>>> True, we need to sort out that. But the selection of the card-level >>>> driver can be relatively easily done in a manual way, either via >>>> blacklisting or by common module options. Currently AMDGPU and radeon >>>> drivers are in such situation, for example. >>>> >>>> A common single switch, or at best the automatic arbitration would be >>>> preferred, of course, though. >>> >>> The switch is again short term as we should progress and move towards one >>> solution whilst deprecating the other, so that way this makes a simple >>> solution and helps in transition, change flag defaults and deprecate. >> >> Sorry, I don't get your point. Are you saying the legacy would be >> deprecated? that was never my understanding, Rakesh's patches only make it >> easier to use the DSP in combination with an HDaudio codec, but if the DSP >> is not present the legacy is the fallback, no? > > for now yes, but what prevents us from supporting coupled mode when DSP is > disabled :) That gets complicated. you'd have 1. DSP-based ASoC driver for SKL+ w/ DSP 2. coupled-mode ASoC driver for SKL+ w/o DSP 3. legacy for pre-SKL platforms. I don't see what simplification this brings, it's complicated enough with 1. and 3, and legacy is not going away.