linux-kernel - Re: audio lost from speaker after reboot from windows on the device ALC295

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Message-ID: <c37fa9bd-071c-6c10-55a6-933a4937fa87@canonical.com>
Date:   Fri, 5 Jul 2019 07:27:00 +0800
From:   Hui Wang <hui.wang@...onical.com>
To:     "He, Bo" <bo.he@...el.com>,
        "kailang@...ltek.com" <kailang@...ltek.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     "perex@...ex.cz" <perex@...ex.cz>,
        "tiwai@...e.com" <tiwai@...e.com>,
        "jian-hong@...lessm.com" <jian-hong@...lessm.com>,
        "drake@...lessm.com" <drake@...lessm.com>,
        "chiu@...lessm.com" <chiu@...lessm.com>
Subject: Re: audio lost from speaker after reboot from windows on the device
 ALC295

Maybe your machine has an external amplifier which needs to be set by 
software before it can work.

On 2019/7/4 下午8:02, He, Bo wrote:
> Hi, patch_realtek.c maintainer:
> 	I see one issue that reboot from windows and boot to ubuntu, the audio lost from speaker, I suspect there are some bugs in patch_realtek.c drivers,  the device is ALC295 and the device id is 0x10ec0295.
>
> I have done the below experiments:
> 1. reboot from windows to windows, the audio is persist .
> 2. reboot from windows to ubuntu, the audio lost from speaker, but can hear if I hotplug one earphone.
> 3. if the issue reproduce after reboot from windows, reboot the ubuntu can't restore the audio, I suspect it's warm reset.
> 4. if I write the port 0xcf9 with 0xe to do cold reset, the audio can restore.
> 5. if I do suspend/resume, the audio can restore, I suspect do cold boot and suspend will trigger the platform reset to reset the ALC295.
> 6. if I do double function reset (write the verb 0x7ff in alc_init), the audio is still can't restore.
> snd_hda_codec_write(codec, 0x01, 0, AC_VERB_SET_CODEC_RESET, 0); /* Function reset */
> snd_hda_codec_write(codec, 0x01, 0, AC_VERB_SET_CODEC_RESET, 0); /* double Function reset */
> 7. the issue is first found on kernel 4.19.50, I still see the issue with the latest kernel 5.2-rc2, is it possible windows change some default registers, but ALC295 don't initialize the register?
>