I dual-booted Ubuntu 15.04 alongside Windows 10. There is a known issue with the audio in linux on this computer: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1441852
The older models that came with windows 8 apparently had a fix: http://h30434.www3.hp.com/t5/Notebook-PC-Sound-and-Audio/HP-spectre-x360-on-linux/td-p/4980797
In summary, the fix was to edit
/etc/default/grub and change the line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash'" to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor acpi_osi='!Windows 2013' acpi_osi='!Windows 2012'", run
update-grub, and reboot twice. You then may/may not have to click audio icon, go to sound settings, and then double click audio device.
I followed these steps, and they do work. The problem is...after I boot into 'Windows Boot Manager' (the only option to boot into windows 10 on grub), and then shut down or restart and boot into ubuntu, the sound device goes away. Running
update-grub and rebooting into ubuntu again will make the audio device return in the audio settings. The changes to
/etc/default/grub persist between all reboots.
Any ideas/advice/insight on how to ensure audio device remains present after booting in ubuntu after booting into windows 10?