Just tested on the affected hardware, and can confirm the new package fixes this bug. After enabling -proposed, running updates, and doing a full shutdown, sound begins working correctly again.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-firmware in Ubuntu. https://bugs.launchpad.net/bugs/1645911 Title: linux-firmware 1.157.5 causes sound issues after initramfs update Status in linux package in Ubuntu: Fix Released Status in linux-firmware package in Ubuntu: Invalid Status in linux source package in Xenial: Confirmed Status in linux-firmware source package in Xenial: Fix Committed Bug description: On laptops with Kaby Lake processors and Sunrise point chipsets (System76 Lemu7), updating to the current (1.157.5) version of the linux-firmware package and then updating initramfs causes sound issues. This can manifest in two ways: 1: Volume hotkeys and controls appear to work, but actual playback volume remains the same. Three HDMI devices appear in the sound-settings gui, despite no HDMI device connected (and only 1 HDMI port) 2: 'Dummy Output' is the only device in the sound-settings gui, and there is no sound output at all. In both cases dmesg shows error output relating to snd_hda_codec_hdmi. This bug only affects Xenial, not Yakkety. Xenial still exhibits the above symptoms after installing the current Yakkety linux-firmware package. I believe the issue is related to the Kaby Lake firmware. In testing, I was able to remove '/lib/firmware/i915/kbl_dmc_ver1_01.bin', run 'sudo update-initramfs -u', and reboot to get sound working correctly again. Perhaps this firmware is needed for the upcoming Union Point chipsets, but causes problems with the for Kaby Lake processor laptops running the 4.4.0 kernel and Sunrise Point chipsets. There is either a bug in the new Kaby Lake firmware or it is being erroneously applied to inappropriate hardware. I have received a number of reports of users running into this bug, presumably anyone who updated to the latest kernel and linux-firmware packages at the same time. Based on testing, next kernel update could trigger the bug for many more users. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1645911/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
