From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Henningsson Subject: Re: [PATCH] ALSA: hda - fix broken HDMI jack detection after S3 Date: Wed, 22 Aug 2012 16:27:35 +0200 Message-ID: <5034EC57.2090503@canonical.com> References: <1345636901-9386-1-git-send-email-david.henningsson@canonical.com> <5034D2F5.3050406@canonical.com> <5034E2D3.1080701@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 C06A526613A for ; Wed, 22 Aug 2012 16:27:34 +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: alsa-devel@alsa-project.org, 1040030@bugs.launchpad.net List-Id: alsa-devel@alsa-project.org On 08/22/2012 03:52 PM, Takashi Iwai wrote: > At Wed, 22 Aug 2012 15:46:59 +0200, > David Henningsson wrote: >> >> On 08/22/2012 02:58 PM, Takashi Iwai wrote: >>> At Wed, 22 Aug 2012 14:39:17 +0200, >>> David Henningsson wrote: >>>> >>>> On 08/22/2012 02:22 PM, Takashi Iwai wrote: >>>>> At Wed, 22 Aug 2012 14:01:41 +0200, >>>>> David Henningsson wrote: >>>>>> >>>>>> The HDMI codec (an NVIDIA one in this case) forgot that its pins >>>>>> were unsol enabled, while it was suspended. Therefore jack detection >>>>>> was broken after S3. >>>>>> With this patch, we reenable the unsol events on resume, >>>>>> and also do an extra check afterwards, to see if the HDMI monitor was >>>>>> plugged/unplugged while in S3. >>>>>> >>>>>> Cc: stable@kernel.org (3.3+) >>>>>> BugLink: https://bugs.launchpad.net/bugs/1040030 >>>>>> Signed-off-by: David Henningsson >>>>>> --- >>>>>> sound/pci/hda/patch_hdmi.c | 13 +++++++++++++ >>>>>> 1 file changed, 13 insertions(+) >>>>>> >>>>>> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c >>>>>> index 8f23374..6a3ac05 100644 >>>>>> --- a/sound/pci/hda/patch_hdmi.c >>>>>> +++ b/sound/pci/hda/patch_hdmi.c >>>>>> @@ -1315,6 +1315,16 @@ static int generic_hdmi_init(struct hda_codec *codec) >>>>>> return 0; >>>>>> } >>>>>> >>>>>> +#ifdef CONFIG_PM >>>>>> +static int generic_hdmi_resume(struct hda_codec *codec) >>>>>> +{ >>>>>> + snd_hda_codec_resume_cache(codec); >>>>>> + snd_hda_jack_set_dirty_all(codec); >>>>>> + snd_hda_jack_report_sync(codec); >>>>>> + return 0; >>>>> >>>>> Hm, is this really needed? >>>>> >>>>> snd_hda_jack_set_dirty_all() is already called in >>>>> hda_call_codec_resume(), and snd_hda_jack_report_sync() is called in >>>>> the init callback. >>>> >>>> The tester (who has the hardware) has gone for the day, so I can't >>>> really verify different scenarios right now, but after having looked at >>>> hda_call_codec_resume I see what you mean... >>>> >>>> I do notice one difference though - the order. >>>> snd_hda_codec_resume_cache, which is what writes the unsol_enable verbs, >>>> should probably be before the set_dirty_all / report_sync. If not for >>>> anything else, so for the race condition of somebody plugging/unplugging >>>> the monitor after checking the jack but before the unsol is enabled. >>> >>> Calling snd_hda_jack_report_sync() in init means that all jacks are >>> checked at first, then the caches are resumed. So this won't change >>> ENABLE_UNSOL verb setups. >> >> I'm not sure I'm following. Here's the order in hda_call_codec_resume: >> >> snd_hda_jack_set_dirty_all() >> generic_hdmi_init -> snd_hda_jack_report_sync() - get_pin_sense >> snd_hda_codec_resume_cache() - set_unsol_enable >> >> With the (theoretical?) race condition being a change of pin sense >> between snd_hda_jack_report_sync() and snd_hda_codec_resume_cache(), >> which will not be picked up. > > In that race, yes. But this should be irrelevant with this bug :) Yes, the bug needs further verification. >> The patch changed the order to: >> >> snd_hda_codec_resume_cache() - set_unsol_enable >> snd_hda_jack_set_dirty_all() >> snd_hda_jack_report_sync() - get_pin_sense >> >> Which eliminates that race condition. > > Well, what I'm thinking now is rather to call > snd_hda_jack_report_sync() generically in hda_call_codec_resume(). > The call doesn't have to be in all places. > Ditto for the initialization case. It'll clean up many lines. Fine with me - the more code being generic, the better. -- David Henningsson, Canonical Ltd. https://launchpad.net/~diwic