我用的 GNOME41.8 桌面，窗口系统 Wayland,无法在设置的电源选项里改亮度，也找不到一些教程里说的这个文件夹：
- $ cat /sys/class/backlight/acpi_video0/max_brightness
cat: /sys/class/backlight/acpi_video0/max_brightness: 没有那个文件或目录
按照这个教程安装了 ddcutil，但是执行 sudo ddcutil setvcp 10 15 命令的时候显示：
VCP (aka MCCS) version for display is undetected or Less than 2.0. Output may not be accurate.
Verification failed for feature 10
原文说 “如果还是不行，那么我建议你执行 ddcutil environment 命令 (针对 i2c 设备)，他会给你一个配置建议”
但我执行完 ddcutil environment 最后一行给的建议 (END 到本文最底下) 啥也没说。
- $ ddcutil environment
The following tests probe the runtime environment using multiple overlapping methods.
*** Basic System Information ***
ddcutil version: 1.4.0
/proc/version:
Linux version 5.14.21-150500.55.59-default (geeko@buildhost) (gcc (SUSE Linux) 7.5.0, GNU ld (GNU Binutils; SUSE Linux Enterprise 15) 2.41.0.20230908-150100.7.46) #1 SMP PREEMPT_DYNAMIC Thu Apr 18 12:59:33 UTC 2024 (e8ae24a)
Architecture: x86_64
Distributor id: sh: lsb_release: 未找到命令
Release: sh: lsb_release: 未找到命令
Found a known architecture
/proc/cmdline:
BOOT_IMAGE=/boot/vmlinuz-5.14.21-150500.55.59-default root=UUID=30d77f53-2f95-4cbb-8d22-7f4983cc7bf2 splash=silent preempt=full mitigations=auto quiet security=apparmor
*** Primary Check 1: Identify video card and driver ***
Obtaining card and driver information from /sys…
Primary video controller at PCI address 0000:00:02.0 (boot_vga flag is set)
Device class: x030000 VGA compatible controller
Vendor: x8086 Intel Corporation
Device: x0412 Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller
Subvendor/Subdevice: 1458/d000 Gigabyte Technology Co., Ltd
Driver name: i915
Driver version: Unable to determine
I2C device: i2c-3 name: i915 gmbus dpc
I2C device: i2c-1 name: i915 gmbus vga
I2C device: i2c-4 name: i915 gmbus dpb
I2C device: i2c-2 name: i915 gmbus panel
I2C device: i2c-0 name: i915 gmbus ssc
I2C device: i2c-5 name: i915 gmbus dpd
*** Primary Check 2: Check that /dev/i2c-* exist and writable ***
Current user: nmmsk (1000)
Checking /dev/i2c-* devices…
Devices /dev/i2c-* must exist and the logged on user must have read/write permission for those devices (or at least those devices associated
with monitors).
Typically, this access is enabled by:
- setting the group for /dev/i2c-* to i2c
- setting group RW permissions for /dev/i2c-*
- making the current user a member of group i2c
Alternatively, this can be enabled by just giving everyone RW permission
The following tests probe for these conditions.
Checking for /dev/i2c-* devices…
crwxrwxrw-+ 1 root root 89, 0 5 月 22 21:02 /dev/i2c-0
crwxrwxrw-+ 1 root root 89, 1 5 月 22 21:02 /dev/i2c-1
crwxrwxrw-+ 1 root root 89, 2 5 月 22 21:02 /dev/i2c-2
crwxrwxrw-+ 1 root root 89, 3 5 月 22 21:02 /dev/i2c-3
crwxrwxrw-+ 1 root root 89, 4 5 月 22 21:02 /dev/i2c-4
crwxrwxrw-+ 1 root root 89, 5 5 月 22 21:02 /dev/i2c-5
crwxrwxrw- 1 root root 89, 6 5 月 22 21:02 /dev/i2c-6
Current user (nmmsk) has RW access to all /dev/i2c-* devices.
*** Primary Check 3: Check that module i2c_dev is loaded ***
Checking for driver i2c_dev…
sysfs reports module i2c_dev is loaded.
Module i2c_dev is NOT built into the kernel
Loadable i2c-dev module found
Module i2c_dev is loaded
*** Primary Check 4: Driver specific checks ***
Performing driver specific checks…
No driver specific checks apply.
*** Additional probes ***
Examining /sys/bus/i2c/devices…
/sys/bus/i2c/devices/i2c-0/name: i915 gmbus ssc
/sys/bus/i2c/devices/i2c-1/name: i915 gmbus vga
/sys/bus/i2c/devices/i2c-2/name: i915 gmbus panel
/sys/bus/i2c/devices/i2c-3/name: i915 gmbus dpc
/sys/bus/i2c/devices/i2c-4/name: i915 gmbus dpb
/sys/bus/i2c/devices/i2c-5/name: i915 gmbus dpd
/sys/bus/i2c/devices/i2c-6/name: SMBus I801 adapter at f040
/sys/bus/i2c/devices/6-0050/name: spd
/sys/bus/i2c/devices/6-0052/name: spd
Env_Accumulator:
architecture: x86_64
distributor_id sh: lsb_release: 未找到命令
Drivers detected: i915
/dev/i2c device numbers: 0 1 2 3 4 5 6
sysfs_i2c_devices_exist: true
/sys/bus/i2c device numbers: 0 1 2 3 4 5 6
dev_i2c_devices_required: true
module_i2c_dev_needed: true
module_i2c_dev_builtin: false
loadable_i2c_dev_exists: true
i2c_dev_loaded_or_builtin: true
group_i2c_checked: true
group_i2c_exists: true
dev_i2c_common_group_name: root
all_dev_i2c_has_group_i2c: false
any_dev_i2c_has_group_i2c: false
all_dev_i2c_is_group_rw: true
any_dev_i2c_is_group_rw: false
cur_uname: nmmsk
cur_uid: 1000
cur_user_in_group_i2c: true
cur_user_any_devi2c_rw: true
cur_user_all_devi2c_rw: true
Configuration suggestions:
Current user has RW access to all /dev/i2c-N devices.
Skipping further group and permission checks.