Hi, I have a Lenovo laptop (L340-17API) which uses an AMD chip for graphics: 04:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Picasso [1002:15d8] (rev c2) It seemed that everything was fine with systemd-backlight before AMD decided to mix using 16-bit and 8-bit values... Now it seems that this was tackled here (https://bugzilla.kernel.org/show_bug.cgi?id=203905) and indeed I don't get this issue anymore, using 5.9 and now 5.9.1 on Arch Linux: Οκτ 07 15:08:56 L340 systemd-backlight[333]: amdgpu_bl0: Saved brightness 22359 too high; decreasing to 255. I don't know if this is related to the 16-bit bug anymore, but I do get this when I boot the laptop: Οκτ 19 12:04:06 L340 systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0... Οκτ 19 12:04:06 L340 systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Main process exited, code=exited, status=1/FAILURE Οκτ 19 12:04:06 L340 systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Failed with result 'exit-code'. Οκτ 19 12:04:06 L340 systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. dmesg gives me this trace: [ +0,000025] ------------[ cut here ]------------ [ +0,000133] WARNING: CPU: 0 PID: 15 at drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link.c:2548 dc_link_set_backlight_level+0x8a/0xf0 [amdgpu] [ +0,000003] Modules linked in: ac(+) acpi_cpufreq(+) tcp_bbr tcp_lp pkcs8_key_parser sg crypto_user ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 serio_raw atkbd libps2 amdgpu crc32c_intel xhci_pci xhci_pci_renesas xhci_hcd i8042 serio gpu_sched i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec rc_core drm agpgart [ +0,000020] CPU: 0 PID: 15 Comm: kworker/0:1 Not tainted 5.9.1-arch1-1 #1 [ +0,000002] Hardware name: LENOVO 81LY/LNVNB161216, BIOS ARCN34WW 05/20/2020 [ +0,000005] Workqueue: kacpi_notify acpi_os_execute_deferred [ +0,000112] RIP: 0010:dc_link_set_backlight_level+0x8a/0xf0 [amdgpu] [ +0,000002] Code: 70 03 00 00 31 c0 48 8d 96 c0 01 00 00 48 8b 0a 48 85 c9 74 06 48 3b 59 08 74 20 83 c0 01 48 81 c2 d8 04 00 00 83 f8 06 75 e3 <0f> 0b 45 31 e4 5b 44 89 e0 5d 41 5c 41 5d 41 5e c3 48 98 48 69 c0 [ +0,000001] RSP: 0018:ffffb8b70014fcc0 EFLAGS: 00010246 [ +0,000002] RAX: 0000000000000006 RBX: ffffa20ff023fc00 RCX: 0000000000000000 [ +0,000001] RDX: ffffa20fee041ed0 RSI: ffffa20fee040000 RDI: 0000000000000000 [ +0,000001] RBP: ffffa20fecd90000 R08: 0000000000000004 R09: 0000000000000001 [ +0,000001] R10: ffffa20ff68f53a8 R11: 0000000000000000 R12: 0000000000000401 [ +0,000001] R13: 0000000000000000 R14: 0000000000000404 R15: 00000000ffffffff [ +0,000002] FS: 0000000000000000(0000) GS:ffffa20ff8a00000(0000) knlGS:0000000000000000 [ +0,000001] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0,000001] CR2: 00007ffd5954be50 CR3: 00000001b5442000 CR4: 00000000003506f0 [ +0,000002] Call Trace: [ +0,000119] amdgpu_dm_backlight_update_status+0xb4/0xc0 [amdgpu] [ +0,000005] backlight_device_set_brightness+0x7e/0x130 [ +0,000107] amdgpu_acpi_event+0x1fb/0x270 [amdgpu] [ +0,000006] blocking_notifier_call_chain+0x5d/0x80 [ +0,000003] acpi_notifier_call_chain+0xa0/0xe0 [ +0,000005] acpi_video_bus_notify+0x139/0x1d0 [ +0,000003] acpi_ev_notify_dispatch+0x4a/0x5f [ +0,000002] acpi_os_execute_deferred+0x16/0x20 [ +0,000003] process_one_work+0x1da/0x3d0 [ +0,000002] worker_thread+0x4d/0x3d0 [ +0,000002] ? rescuer_thread+0x410/0x410 [ +0,000002] kthread+0x142/0x160 [ +0,000002] ? __kthread_bind_mask+0x60/0x60 [ +0,000003] ret_from_fork+0x22/0x30 [ +0,000003] ---[ end trace d03f36eba464d928 ]--- If I restart systemd-backlight@backlight:amdgpu_bl0.service it works fine, and restores the previous backlight level, so looking at this forum post (https://archlinux.org.ru/forum/topic/20262/?page=1#post-235818) I edited the service like so: # /etc/systemd/system/systemd-backlight@backlight:amdgpu_bl0.service.d/override.co nf [Service] Restart=on-failure RestartSec=5s Now I get this at boot (fails, then works): Οκτ 19 12:32:11 L340 systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0... Οκτ 19 12:32:11 L340 systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Main process exited, code=exited, status=1/FAILURE Οκτ 19 12:32:11 L340 systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Failed with result 'exit-code'. Οκτ 19 12:32:11 L340 systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. Οκτ 19 12:32:16 L340 systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Scheduled restart job, restart counter is at 1. Οκτ 19 12:32:16 L340 systemd[1]: Stopped Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. Οκτ 19 12:32:16 L340 systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0... Οκτ 19 12:32:16 L340 systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. I have tried acpi_backlight=video and native but then the systemd-backlight service finishes successfully, "restoring" max brightness. _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
