Score:0

Brightness and sound not working after downgrading to 18.04 from 20.04 on dell latitude 3420 intel iris graphics

mx flag
ntg

I have received my laptop(dell latitude 3420) pre-installed with ubuntu 20.04, as there is a personal requirement I have removed 20.04 and installed 18.04. After installing 18.04 I found sound is not working(at output it is showing dummy output and input is not being detected) and couldn't find brightness bar.

I have also updated the bios to recent bios provided by vendor. After finding few solutions on the internet I tried changing GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" in /etc/default/grub. Then I could just see the brightness bar but nothing is changing even though if i use the slider bar. The Kernel version is: Linux 5.4.0-86-generic. And I also noticed this folder /sys/class/backlight/ is empty.

Although my hardware has intel iris xe graphics in the settings details it is showing llvmpipe (LLVM 10.0.0, 256 bits). So, can someone please help me solving the brightness and sound issue. Thanks in advance.

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.