From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Henningsson Subject: Re: [PATCH 1/2] ALSA: hda - Continue probing even if i915 binding fails Date: Fri, 12 Jun 2015 16:33:32 +0200 Message-ID: <557AEDBC.8060305@canonical.com> References: <1433931965-12337-1-git-send-email-tiwai@suse.de> <557A7968.1040801@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) by alsa0.perex.cz (Postfix) with ESMTP id EFDEC260494 for ; Fri, 12 Jun 2015 16:33:32 +0200 (CEST) In-Reply-To: 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: Takashi Iwai Cc: "Yang, Libin" , "Lin, Mengdong" , "alsa-devel@alsa-project.org" List-Id: alsa-devel@alsa-project.org On 2015-06-12 16:14, Takashi Iwai wrote: > At Fri, 12 Jun 2015 08:37:38 +0200, > Takashi Iwai wrote: >> >> At Fri, 12 Jun 2015 08:17:12 +0200, >> David Henningsson wrote: >>> If BIOS disables the power well, then we would get the "audio register >>> I/O error" in the boot phase, there will be no codecs detected, and thus >>> no broken sound card showing up. >>> >>> The only issue is if the i915 driver disables the power well, but the >>> case that the i915 should be functioning enough to turn off the power >>> well at some point, and at the same time so broken that we can't bind to >>> it, seems extremely unlikely to me. >>> >>> Either the i915 driver works, or it does not. In both cases, continuing >>> probing is the more useful option. >> >> I don't see much usefulness there but rather simplicity. >> >> The binding with i915 won't happen at the later stage, thus the device >> is just a placeholder. Any other goodies by keeping the dead device? >> >>>> Fair enough. Then I'm going to queue the patch below in addition to >>>> for-linus branch. >>> >>> We'll have to agree to disagree on that, then. >> >> One point that hasn't been mentioned is the behavior change from the >> previous kernels. The previous kernels abort probing, and it was OK >> since we supposed only HSW/BDW before 4.1. Now, with continuing the >> probe, user sees the new device that hasn't been there, and yet the >> device is dead and merely a placeholder. > > Is this convincing enough for you? Or would you still like to make > the broken HDMI/DP device enabled for HSW/BDW? I guess the question is whether HDMI/DP can actually work without the i915 driver, e g when running with nomodeset. If there is absolutely no possibility whatsoever (e g maybe BIOS could set up the device so that it works?), then it does not matter much, I suppose. -- David Henningsson, Canonical Ltd. https://launchpad.net/~diwic