I've just installed a fresh new Debian 9 LXDE into an ACER AMD Notebook and everything seems to be working fine. However, during the boot, there is an annoying Strong Backlight Flash (seems like a photo flash). The sequence of events are basically as following:
- Boot starts at maximum backlight brightness
- Debian OS is selected at GRUB menu
- Some messages appear in low resolution at the command line
- Strong Backlight Flash
- Command line is now in high resolution
- Backlight Brightness is set to user pre-defined level
- LXDE login screen
Considering that during the Windows era of this notebook such flash never happened, I'm pretty sure there is a way via software to avoid that.
Question
How to avoid this Strong Backlight Flash?
Debug
root@debian:~# dmesg | grep -i "error\|firmware\|backlight"
[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.9.0-6-amd64 root=UUID=740fe980-f018-4c49-b139-613d41d30fb9 ro quiet acpi_backlight=video
[ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.9.0-6-amd64 root=UUID=740fe980-f018-4c49-b139-613d41d30fb9 ro quiet acpi_backlight=video
[ 0.294171] ACPI: [Firmware Bug]: BIOS _OSI(Linux) query ignored
[ 0.311772] acpi PNP0A08:00: [Firmware Info]: MMCONFIG for domain 0000 [bus 00-3f] only partially covers this bridge
[ 1.057843] pci 0000:01:00.0: [Firmware Bug]: disabling VPD access (can't determine size of non-standard VPD format)
[ 7.131791] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[ 12.551069] radeon 0000:00:01.0: firmware: direct-loading firmware radeon/PALM_pfp.bin
[ 12.685950] radeon 0000:00:01.0: firmware: direct-loading firmware radeon/PALM_me.bin
[ 12.705633] radeon 0000:00:01.0: firmware: direct-loading firmware radeon/SUMO_rlc.bin
[ 12.762705] radeon 0000:00:01.0: firmware: direct-loading firmware radeon/SUMO_uvd.bin
[ 13.481390] [drm] radeon atom DIG backlight initialized
Hardware Specifications
Notebook Aspire E1-421-0622 | product details
- AMD 2 Core™ Processor E1-1200 (1.4 GHz) 1MB Cache 64-bit Processing
- AMD Radeon HD 7310 Graphics Controller
- 2Gb DDR3 SDRAM Memory
- 256MB shared video memory
Debian Strech
debian-9.4.0-amd64-netinst.iso
- Software selection
( ) Debian desktop environment
( ) ... GNOME
( ) ... Xfce
( ) ... KDE
( ) ... Cinnamon
( ) ... MATE
(X) ... LXDE
( ) web server
(X) print server
( ) SSH server
(X) standard system utilities Minor adjustments:
- Non-free package
firmware-amd-graphics
installed (full discussion) /etc/default/grub
file updated (full discussion):GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=video"
- Non-free package