So I have tested your custom kernel. It does not fix my problem: -if the brightness == max_brightness => the display is at max brightness but stable. -if the brightness < max_brightness => the display brightness is not stable (is flashing). the brightness is jumping back and fort on the value brightness and max_brightness
But the values are as you described (actual_brightness is equal brightness) Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat brightness 183 Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat actual_brightness 183 Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat max_brightness 255 Please tell me if I can test anything! Actually I have an other laptop Asus 315-41, but with discrete GPU with the same OS, it has the also a large actual_brightness value, but the brightness control works (as you described with the laptops you tested)... I'm not sure how long the other laptop will work correctly... :( -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1861925 Title: BrightnessOutofRange: Actual brightness for amdgpu_bl0 not in range 0..255 Status in linux package in Ubuntu: Incomplete Bug description: Hi, I have a acer aspire a315-41 laptop, it has BIOS 1.15, Ubuntu 19.10, Kernel stock 5.3, and 5.5.0. I have a problem with the Backlight. I can not control. According to: https://wiki.ubuntu.com/Kernel/Debugging/Backlight It is : Backlight control does not work, but there are entries in /sys/class/backlight. The problem is as far I could find: sanya@Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat brightness 135 sanya@Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat actual_brightness 43500 sanya@Aspire-A315-41:/sys/class/backlight/amdgpu_bl0$ cat max_brightness 255 The brightness read from the HW is not in the range, and when I change the brightness by the keys the value in the brightness file changes too, but the actual_brightness is stuck at the value 43500... I have tried all the steps mentioned in https://wiki.ubuntu.com/Kernel/Debugging/Backlight Actually I have tried all these kernel startup parameter variants without luck: GRUB_CMDLINE_LINUX_DEFAULT="" #GRUB_CMDLINE_LINUX_DEFAULT="video.use_native_backlight=1" #GRUB_CMDLINE_LINUX_DEFAULT="acpi_osi=" #GRUB_CMDLINE_LINUX_DEFAULT="video.use_bios_initial_backlight=0" #GRUB_CMDLINE_LINUX_DEFAULT="amdgpu.dcfeaturemask=0x4 amdgpu.abmlevel=2" #GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=video amdgpu.abmlevel=1" #GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp acpi_osi=Linux acpi_backlight=vendor" #GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp acpi_osi=! acpi_osi=\"Windows 2009\" acpi_backlight=vendor" #GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp acpi_osi=! acpi_osi=\"Windows 2009\" acpi_backlight=video" #GRUB_CMDLINE_LINUX_DEFAULT="acpi_osi=! acpi_osi=\"Windows 2009\" acpi_backlight=vendor" #GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp acpi_osi=! acpi_osi=\"Windows 2009\" acpi_backlight=vendor" #GRUB_CMDLINE_LINUX_DEFAULT="i8042.nopnp acpi_osi=! acpi_osi=\"Windows 2009\" acpi_backlight=vendor" I guess the fwts has found also this as an error: autobrightness: Automated LCD brightness test. -------------------------------------------------------------------------------- Test 1 of 2: Test for maximum and actual brightness. PASSED: Test 1, Maximum brightness for amdgpu_bl0 is 255 which is sane. FAILED [HIGH] BrightnessOutofRange: Test 1, Actual brightness for amdgpu_bl0 not in range 0..255. Test 2 of 2: Change actual brightness. FAILED [MEDIUM] BrightnessMismatch: Test 2, 256 brightness levels did not match the brightnesss level just set for backlight amdgpu_bl0. The failed brightness levels were: 0-255. It would be great if someone could help set the HW brightness back to the normal range. If you need any more debug files please let me know! Thanks, Regards, Sandor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1861925/+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
