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?

Sorry!! Forgot attach file.

-----Original Message----- From: Kailang Sent: Friday, July 5, 2019 10:41 AM To: 'He, Bo' bo.he@intel.com; alsa-devel@alsa-project.org; linux-kernel@vger.kernel.org Cc: perex@perex.cz; tiwai@suse.com; jian-hong@endlessm.com; drake@endlessm.com; chiu@endlessm.com; hui.wang@canonical.com Subject: RE: audio lost from speaker after reboot from windows on the device ALC295

Hi Bo He,

Could you help to dump info for us? Please use attach file to get results.

./alsa-info.sh --no-upload

You will find dump file in folder /tmp/alsa-info.txt-????????.

Please run one time in normal state and one time in fail state. Please send two result files to me.

BR, Kailang

...

-----Original Message----- From: He, Bo bo.he@intel.com Sent: Thursday, July 4, 2019 8:02 PM To: Kailang kailang@realtek.com; alsa-devel@alsa-project.org; linux-kernel@vger.kernel.org Cc: perex@perex.cz; tiwai@suse.com; jian-hong@endlessm.com; drake@endlessm.com; chiu@endlessm.com; hui.wang@canonical.com Subject: audio lost from speaker after reboot from windows on the device ALC295

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?

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