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#1 2020-12-01 22:38:30

Archemore
Member
Registered: 2020-11-12
Posts: 17

[SOLVED] Backlight/amdgpu sometimes fails at boot

Hi all,

For many months now I've had occasional problems booting, where the screen will suddenly go black and sit presumably forever like that until I hold the power button to restart. The problem is that this happens inconsistently, and often the next reboot will start up totally normally. There are a few anecdotal patterns I noticed over the time I've experienced this:

  • Some mainline kernels have been better than others; I remember this problem happening much less frequently a few months ago, but it's gotten worse in the last few kernel upgrades.

  • The LTS kernel seems to avoid this problem much more frequently, but has also had this issue a rare number of times.

  • Booting into the LTS kernel, and then trying the regular one right after seems to increase the chance of a successful boot.

Here is the output of lspci -v for my laptop info before going forward:

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Root Complex
	Subsystem: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Root Complex
	Flags: fast devsel

00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 IOMMU
	Subsystem: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 IOMMU
	Flags: bus master, fast devsel, latency 0, IRQ 25
	Capabilities: <access denied>

00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge
	Flags: fast devsel, IOMMU group 0

00:01.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 PCIe GPP Bridge [6:0] (prog-if 00 [Normal decode])
	Flags: bus master, fast devsel, latency 0, IRQ 26, IOMMU group 1
	Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
	I/O behind bridge: [disabled]
	Memory behind bridge: d0900000-d09fffff [size=1M]
	Prefetchable memory behind bridge: [disabled]
	Capabilities: <access denied>
	Kernel driver in use: pcieport

00:01.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 PCIe GPP Bridge [6:0] (prog-if 00 [Normal decode])
	Flags: bus master, fast devsel, latency 0, IRQ 27, IOMMU group 2
	Bus: primary=00, secondary=02, subordinate=02, sec-latency=0
	I/O behind bridge: 00002000-00002fff [size=4K]
	Memory behind bridge: d0800000-d08fffff [size=1M]
	Prefetchable memory behind bridge: [disabled]
	Capabilities: <access denied>
	Kernel driver in use: pcieport

00:01.3 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 PCIe GPP Bridge [6:0] (prog-if 00 [Normal decode])
	Flags: bus master, fast devsel, latency 0, IRQ 28, IOMMU group 3
	Bus: primary=00, secondary=03, subordinate=03, sec-latency=0
	I/O behind bridge: [disabled]
	Memory behind bridge: d0700000-d07fffff [size=1M]
	Prefetchable memory behind bridge: [disabled]
	Capabilities: <access denied>
	Kernel driver in use: pcieport

00:01.6 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 PCIe GPP Bridge [6:0] (prog-if 00 [Normal decode])
	Flags: bus master, fast devsel, latency 0, IRQ 29, IOMMU group 4
	Bus: primary=00, secondary=04, subordinate=04, sec-latency=0
	I/O behind bridge: 00003000-00003fff [size=4K]
	Memory behind bridge: d0600000-d06fffff [size=1M]
	Prefetchable memory behind bridge: 00000000d0a00000-00000000d0bfffff [size=2M]
	Capabilities: <access denied>
	Kernel driver in use: pcieport

00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge
	Flags: fast devsel, IOMMU group 5

00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Internal PCIe GPP Bridge 0 to Bus A (prog-if 00 [Normal decode])
	Flags: bus master, fast devsel, latency 0, IRQ 30, IOMMU group 6
	Bus: primary=00, secondary=05, subordinate=05, sec-latency=0
	I/O behind bridge: 00001000-00001fff [size=4K]
	Memory behind bridge: d0200000-d05fffff [size=4M]
	Prefetchable memory behind bridge: 00000000c0000000-00000000d01fffff [size=258M]
	Capabilities: <access denied>
	Kernel driver in use: pcieport

00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 61)
	Subsystem: Lenovo ThinkPad E595
	Flags: 66MHz, medium devsel, IOMMU group 7
	Kernel driver in use: piix4_smbus
	Kernel modules: i2c_piix4, sp5100_tco

00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, 66MHz, medium devsel, latency 0, IOMMU group 7

00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 0
	Flags: fast devsel, IOMMU group 8

00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 1
	Flags: fast devsel, IOMMU group 8

00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 2
	Flags: fast devsel, IOMMU group 8

00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 3
	Flags: fast devsel, IOMMU group 8
	Kernel driver in use: k10temp
	Kernel modules: k10temp

00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 4
	Flags: fast devsel, IOMMU group 8

00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 5
	Flags: fast devsel, IOMMU group 8

00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 6
	Flags: fast devsel, IOMMU group 8

00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 Device 24: Function 7
	Flags: fast devsel, IOMMU group 8

01:00.0 Non-Volatile memory controller: Union Memory (Shenzhen) Device 2263 (rev 03) (prog-if 02 [NVM Express])
	Subsystem: Union Memory (Shenzhen) Device 1cc4
	Flags: bus master, fast devsel, latency 0, IRQ 31, NUMA node 0, IOMMU group 9
	Memory at d0900000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: nvme

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 10)
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 69, IOMMU group 10
	I/O ports at 2000 [size=256]
	Memory at d0804000 (64-bit, non-prefetchable) [size=4K]
	Memory at d0800000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: r8169
	Kernel modules: r8169

03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader (rev 01)
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 49, IOMMU group 11
	Memory at d0700000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: <access denied>
	Kernel driver in use: rtsx_pci
	Kernel modules: rtsx_pci

04:00.0 Network controller: Intel Corporation Wireless-AC 9260 (rev 29)
	Subsystem: Intel Corporation Device 0014
	Physical Slot: 0
	Flags: bus master, fast devsel, latency 0, IRQ 75, IOMMU group 12
	Memory at d0600000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: iwlwifi
	Kernel modules: iwlwifi

05:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev c1) (prog-if 00 [VGA controller])
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 86, IOMMU group 13
	Memory at c0000000 (64-bit, prefetchable) [size=256M]
	Memory at d0000000 (64-bit, prefetchable) [size=2M]
	I/O ports at 1000 [size=256]
	Memory at d0500000 (32-bit, non-prefetchable) [size=512K]
	Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
	Capabilities: <access denied>
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu

05:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Raven/Raven2/Fenghuang HDMI/DP Audio Controller
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 73, IOMMU group 14
	Memory at d05c8000 (32-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel

05:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) Platform Security Processor
	Subsystem: Lenovo ThinkPad E595
	Flags: fast devsel, IRQ 10, IOMMU group 14
	Memory at d0400000 (32-bit, non-prefetchable) [size=1M]
	Memory at d05cc000 (32-bit, non-prefetchable) [size=8K]
	Capabilities: <access denied>

05:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Raven USB 3.1 (prog-if 30 [XHCI])
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 50, IOMMU group 14
	Memory at d0200000 (64-bit, non-prefetchable) [size=1M]
	Capabilities: <access denied>
	Kernel driver in use: xhci_hcd
	Kernel modules: xhci_pci

05:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Raven USB 3.1 (prog-if 30 [XHCI])
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 59, IOMMU group 14
	Memory at d0300000 (64-bit, non-prefetchable) [size=1M]
	Capabilities: <access denied>
	Kernel driver in use: xhci_hcd
	Kernel modules: xhci_pci

05:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] Raven/Raven2/FireFlight/Renoir Audio Processor
	Subsystem: Lenovo ThinkPad E595
	Flags: fast devsel, IRQ 69, IOMMU group 14
	Memory at d0580000 (32-bit, non-prefetchable) [size=256K]
	Capabilities: <access denied>
	Kernel modules: snd_pci_acp3x

05:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 10h-1fh) HD Audio Controller
	Subsystem: Lenovo ThinkPad E595
	Flags: bus master, fast devsel, latency 0, IRQ 74, IOMMU group 14
	Memory at d05c0000 (32-bit, non-prefetchable) [size=32K]
	Capabilities: <access denied>
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel

After investigating some logs, I think I've honed in on an issue involving systemd-backlight@backlight:amdgpu_b10. Here is a comparison of snippets from # journalctl -b and # journalctl -b -1 respectively (with my own emphasis at the start of the lines I think may be most relevant).

Successful boot (using LTS kernel):

---
Dec 01 16:13:16 arch-pc kernel: [drm] Initialized amdgpu 3.35.0 20150101 for 0000:05:00.0 on minor 0
Dec 01 16:13:16 arch-pc systemd[1]: Created slice system-systemd\x2dbacklight.slice.
Dec 01 16:13:16 arch-pc systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Dec 01 16:13:16 arch-pc systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0...
Dec 01 16:13:16 arch-pc kernel: uvcvideo: Found UVC 1.00 device Integrated Camera (04f2:b604)
Dec 01 16:13:16 arch-pc systemd-backlight[844]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device
Dec 01 16:13:16 arch-pc systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
Dec 01 16:13:16 arch-pc systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.
Dec 01 16:13:16 arch-pc systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.
Dec 01 16:13:16 arch-pc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:acpi_video0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
---->Dec 01 16:13:16 arch-pc systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0.
---->Dec 01 16:13:16 arch-pc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:amdgpu_bl0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Dec 01 16:13:16 arch-pc kernel: input: Integrated Camera: Integrated C as /devices/pci0000:00/0000:00:08.1/0000:05:00.4/usb3/3-2/3-2:1.0/input/input16
---

Unsuccessful boot / backlight failure (using mainline kernel):

---
Dec 01 16:11:44 arch-pc kernel: [drm] Initialized amdgpu 3.39.0 20150101 for 0000:05:00.0 on minor 0
Dec 01 16:11:44 arch-pc systemd[1]: Created slice system-systemd\x2dbacklight.slice.
Dec 01 16:11:44 arch-pc systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Dec 01 16:11:44 arch-pc systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0...
Dec 01 16:11:44 arch-pc systemd-backlight[1167]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device
Dec 01 16:11:44 arch-pc systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
Dec 01 16:11:44 arch-pc systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.
Dec 01 16:11:44 arch-pc systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.
Dec 01 16:11:44 arch-pc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:acpi_video0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
---->Dec 01 16:11:44 arch-pc systemd-backlight[1168]: amdgpu_bl0: Failed to write system 'brightness' attribute: No such device or address
---->Dec 01 16:11:44 arch-pc systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Main process exited, code=exited, status=1/FAILURE
---->Dec 01 16:11:44 arch-pc systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Failed with result 'exit-code'.
---->Dec 01 16:11:44 arch-pc systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0.
---->Dec 01 16:11:44 arch-pc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:amdgpu_bl0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Dec 01 16:11:44 arch-pc kernel: ------------[ cut here ]------------
Dec 01 16:11:44 arch-pc kernel: WARNING: CPU: 4 PID: 1168 at drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link.c:2548 dc_link_set_backlight_level+0x8a/0xf0 [amdgpu]
Dec 01 16:11:44 arch-pc kernel: Modules linked in: amdgpu joydev mousedev snd_hda_codec_conexant gpu_sched snd_hda_codec_generic i2c_algo_bit snd_hda_codec_hdmi ttm snd_hda_intel snd_inte>
Dec 01 16:11:44 arch-pc kernel:  xt_addrtype xt_tcpudp xt_conntrack ip6table_filter ip6_tables nf_conntrack_netbios_ns nf_conntrack_broadcast nf_nat_ftp nf_nat nf_conntrack_ftp nf_conntra>
Dec 01 16:11:44 arch-pc kernel: CPU: 4 PID: 1168 Comm: systemd-backlig Not tainted 5.9.11-arch2-1 #1
Dec 01 16:11:44 arch-pc kernel: Hardware name: LENOVO 20NF0018US/20NF0018US, BIOS R11ET28W (1.08 ) 07/31/2019
Dec 01 16:11:44 arch-pc kernel: RIP: 0010:dc_link_set_backlight_level+0x8a/0xf0 [amdgpu]
Dec 01 16:11:44 arch-pc kernel: 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 >
Dec 01 16:11:44 arch-pc kernel: RSP: 0018:ffffb93240b1bdf0 EFLAGS: 00010246
Dec 01 16:11:44 arch-pc kernel: RAX: 0000000000000006 RBX: ffff9ebfdef81400 RCX: 0000000000000000
Dec 01 16:11:44 arch-pc kernel: RDX: ffff9ebfda781ed0 RSI: ffff9ebfda780000 RDI: 0000000000000000
Dec 01 16:11:44 arch-pc kernel: RBP: ffff9ebfda6d0000 R08: 00000000000000ff R09: 000000000000000a
Dec 01 16:11:44 arch-pc kernel: R10: 000000000000000a R11: f000000000000000 R12: 000000000000ff01
Dec 01 16:11:44 arch-pc kernel: R13: 0000000000000000 R14: 000000000000ffff R15: ffff9ebfe9f32260
Dec 01 16:11:44 arch-pc kernel: FS:  00007f49080bf200(0000) GS:ffff9ebff8f00000(0000) knlGS:0000000000000000
Dec 01 16:11:44 arch-pc kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Dec 01 16:11:44 arch-pc kernel: CR2: 00007f9187fb4020 CR3: 000000019a418000 CR4: 00000000003506e0
Dec 01 16:11:44 arch-pc kernel: Call Trace:
Dec 01 16:11:44 arch-pc kernel:  amdgpu_dm_backlight_update_status+0xb4/0xc0 [amdgpu]
Dec 01 16:11:44 arch-pc kernel:  backlight_device_set_brightness+0x7e/0x130
Dec 01 16:11:44 arch-pc kernel:  brightness_store+0x63/0x80
Dec 01 16:11:44 arch-pc kernel:  kernfs_fop_write+0xce/0x1b0
Dec 01 16:11:44 arch-pc kernel:  vfs_write+0xc7/0x210
Dec 01 16:11:44 arch-pc kernel:  ksys_write+0x67/0xe0
Dec 01 16:11:44 arch-pc kernel:  do_syscall_64+0x33/0x40
Dec 01 16:11:44 arch-pc kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Dec 01 16:11:44 arch-pc kernel: RIP: 0033:0x7f4908ed8f67
Dec 01 16:11:44 arch-pc kernel: Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 >
Dec 01 16:11:44 arch-pc kernel: RSP: 002b:00007ffddc6516b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
Dec 01 16:11:44 arch-pc kernel: RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f4908ed8f67
Dec 01 16:11:44 arch-pc kernel: RDX: 0000000000000004 RSI: 00007ffddc6517a0 RDI: 0000000000000004
Dec 01 16:11:44 arch-pc kernel: RBP: 00007ffddc6517a0 R08: 0000000000000000 R09: 0000000000000000
Dec 01 16:11:44 arch-pc kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
Dec 01 16:11:44 arch-pc kernel: R13: 000055e242d613c0 R14: 0000000000000004 R15: 00007f4908fab720
Dec 01 16:11:44 arch-pc kernel: ---[ end trace 536de0d51577fda8 ]---
---

The error about acpi_video0 appears consistently but harmless from what I've read. (It always appears even during successful boots.) Everything on the system is update to date, e.g. mesa, xorg-server, etc. If there's anything I should provide that would be helpful, please let me know. Otherwise, does anyone have some suggestions on things I should try? Due to the unpredictable nature of the issue, it makes it tough to actually conduct scientific experiments, but I'd try some possible solutions to see if the problem goes away. One interesting difference is the version of amdgpu (3.35 good vs 3.39 bad), but I can't imagine that being the source since the regular kernel can boot successfully still.

Last edited by Archemore (2020-12-03 05:21:39)

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#2 2020-12-01 22:54:12

icar
Member
Registered: 2020-07-31
Posts: 562

Re: [SOLVED] Backlight/amdgpu sometimes fails at boot

Can you try things talked in here? https://bbs.archlinux.org/viewtopic.php?id=260919

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#3 2020-12-02 03:42:55

Archemore
Member
Registered: 2020-11-12
Posts: 17

Re: [SOLVED] Backlight/amdgpu sometimes fails at boot

icar wrote:

Can you try things talked in here? https://bbs.archlinux.org/viewtopic.php?id=260919

I tried a few things in that thread but seem to have gone two steps back instead. First, I tried to upgrade my BIOS following this guide, but my laptop wouldn't boot from the usb. (Just a black screen with a blinking prompt.)

In the restarting process, I decided to try some of the kernel parameters suggested in the thread. First, I tried acpi_backlight=video which just gave an immediate black screen. Then I tried amdgpu.gpu_recovery=1. This also didn't work.

After restarting normally, the system booted fine and I tried digging through the journals to see what happened. However, something strange happened: my journal seems to have gotten corrupted in the process somehow. Running # journalctl -b -1 now produces a journal log back from August, and while # journalctl -b produces a log from the current boot, the header is dated from June. Even worse, # journalctl --list-boots seems to have a correct list of boots by date/time, except the last (current) entry, which reads:

   0 90340963b0b344dd9efe36033a09ff04 Sat 2020-12-26 03:49:46 EST—Thu 2020-07-23 20:28:41 EDT

How could doing what I did somehow mess up the journal this bad? Or could this be a bug with the latest kernel? Running # journalctl --verify outputs all passes.

Edit: Even stranger, running just $ journalctl -b -1 produces the correct boot log, but with limited output since not run as root. Also, $journalctl --list-boots seems to be the correct list...

Last edited by Archemore (2020-12-02 03:59:50)

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#4 2020-12-03 05:25:04

Archemore
Member
Registered: 2020-11-12
Posts: 17

Re: [SOLVED] Backlight/amdgpu sometimes fails at boot

Update: I was able to get the BIOS update to work, which went smoothly. However, after that I then found it impossible to boot under any circumstances (either kernel, various parameters...) though GRUB was fine. I decided it was about time to switch from a BIOS boot to UEFI since that was on my to-do list for a while.

So sorry to anyone from the future with a similar problem, but I ended up reinstalling with a UEFI boot as normal. Still, I found errors when using LightDM, so I switched from that to GDM. After a few test reboots, it seems to be stable, so I'll considered this "solved" though a bit anti-climactic. I'll continue to monitor if I have any trouble booting with the new setup.

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