Thinkpad t495 issues

Support
1

Hi!

I am newbie to Linux (2 months). Last month my father gave me his thinkpad t495 with dockstation. I tried to install any distributive with Kde (yea, I love it with all my heart)

Results:

  1. Kubuntu have big with sddm and usb’s

  2. Fedora 32 didn’t autoinstalled Grub and not mounted /home

  3. Installing Ubuntu and then changing from gnome to Kde had less problems, but 3 days after when I entered from sddm I saw dark screen (I was able to use yakuake terminal but I was not able to see mouse pointer.)

  4. Manjaro. I love it because I have it on pc, so I tried to install it firstly, BUT:

a) Micro sd port mount Micro sd card only when boots

b) every time I turn on/turn off/reboot laptop it freezes and on screen there is “failed to start load/save ness of backlight:acpi_video0”

c) USB devices don’t work

d) advantage of manjaro for me is that it worked without troubles with screen

What I have to do?

2

a) try with USB iso

b) see this link ( search is dynamic )

c) can you return

inxi -Fxxxza --no-host
sudo lsusb -vt
3

b) i have a thinkpad e495 and had a kernel error about acpi and display as well. there are helpful tips in the arch wiki. you can try the tips listed for the e485, e585, and e595:
https://wiki.archlinux.org/index.php/ThinkPad#E_series

setting amd_iommu=pt ivrs_ioapic[32]=00:14.0 as kernel parameter solved this problem for me.

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5

add

in this file
/etc/default/grub
line GRUB_CMDLINE_LINUX_DEFAULT
“amd_iommu=pt ivrs_ioapic[32]=00:14.0”

sudo nano /etc/default/grub
sudo update-grub

then reboot

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7

Thank you for this.

However, mine does not save the backlight settings.

This is what “systemctl status systemd-backlight@backlight:amdgpu_bl0” gives me.

● systemd-backlight@backlight:amdgpu_bl0.service - Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0
Loaded: loaded (/usr/lib/systemd/system/systemd-backlight@.service; static; vendor preset: disabled)
Active: active (exited) since Sun 2020-08-23 13:53:51 CEST; 40s ago
Docs: man:systemd-backlight@.service(8)
Process: 903 ExecStart=/usr/lib/systemd/systemd-backlight load backlight:amdgpu_bl0 (code=exited, status=0/SUCCESS)
Main PID: 903 (code=exited, status=0/SUCCESS)

aug 23 13:53:51 t495 systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0…
aug 23 13:53:51 t495 systemd-backlight[903]: amdgpu_bl0: Saved brightness 7374 too high; decreasing to 255.
aug 23 13:53:51 t495 systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0.

Anyone got any ideas?

8

There is a script as a temporary workaround for that backlight issue.

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9