Random crashes, system freezes

[GreyGeek]

No, it is because the files in /sys/ are red-only, and only for the root user, so no one can write to it, if it is present.

ls -la /sys/module/i915/parameters/ | grep rc6
-r-------- 1 root root 4096 May 29 18:33 enable_rc6

Likely this needs to be set in grub somewhere, but I think this tweak may not be necessary in newer kernels, such as in 18.04

Perhaps, in your system, but not on mine, which has several set as rw since the install.
That echo command was found here:

https://askubuntu.com/questions/1082...intel-graphics
and is a common method for setting memory variables "on the fly".

Your kernel method, to set kernel module parameters, is one way, my method is another.
https://wiki.archlinux.org/index.php/Kernel_module

I usually don't recommend editing kernel lines in grub because a lot of people unfamiliar with grub and editing the kernel line end up at a "grub rescue" prompt and unable to continue, so they simply cycle the power button.

An even newer method is to use sysctl in conjunction with /etc/sysctl.d, but I am not comfortable with that method yet, and may never be. I suspect that it will be replacing kernel and module.d mod configurations in the future because it is aligned with systemd.
http://manpages.ubuntu.com/manpages/.../sysctl.8.html
and:
https://unix.stackexchange.com/quest...f-and-sysctl-d

Checking the value of a sysctl variable is as easy as
sysctl <variable name>

and, by the way, setting a sysctl variable is as straightforward as
sudo sysctl -w <variable name>=<value>

but changes made this way will probably hold only till the next reboot.

As to which of the config locations, /etc/sysctl.conf or /etc/sysctl.d/, takes precedence, here is what /etc/sysctl.d/README file says: "End-users can use 60-*.conf and above, or use/etc/sysctl.conf directly, which overrides anything in this directory."

After editing the config in any of the two locations, the changes can be applied with
sudo sysctl -p

Those settings can be set by creating an i915.conf file in /etc/modprobe.d/ and adding options in the form:
options i915 enable_rc6=0
options i915 parm=value
etc...

With some modules one can use "rmmod mod" as root to remove a kernel module and then "modprob mod parm=value", for example "modprobe i915 enable_rc6=0" to turn off power management, which is often the reason for freezing in these cases.

Here are all the parms for the i915 driver:

:~$ [B]modinfo i915 -p[/B]
modeset:Use kernel modesetting [KMS] (0=disable, 1=on, -1=force vga console preference [default]) (int)
panel_ignore_lid:Override lid status (0=autodetect, 1=autodetect disabled [default], -1=force lid closed, -2=force lid open) (int)
semaphores:Use semaphores for inter-ring sync (default: -1 (use per-chip defaults)) (int)
[B]enable_rc6[/B]:Enable power-saving render C-state 6. Different stages can be selected via bitmask values (0 = disable; 1 = enable rc6; 2 = enable deep rc6; 4 = enable deepest rc6). For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. default: -1 (use per-chip default) (int)
enable_dc:Enable power-saving display C-states. (-1=auto [default]; 0=disable; 1=up to DC5; 2=up to DC6) (int)
enable_fbc:Enable frame buffer compression for power savings (default: -1 (use per-chip default)) (int)
lvds_channel_mode:Specify LVDS channel mode (0=probe BIOS [default], 1=single-channel, 2=dual-channel) (int)
lvds_use_ssc:Use Spread Spectrum Clock with panels [LVDS/eDP] (default: auto from VBT) (int)
vbt_sdvo_panel_type:Override/Ignore selection of SDVO panel mode in the VBT (-2=ignore, -1=auto [default], index in VBT BIOS table) (int)
reset:Attempt GPU resets (default: true) (bool)
error_capture:Record the GPU state following a hang. This information in /sys/class/drm/card<N>/error is vital for triaging and debugging hangs. (bool)
enable_hangcheck:Periodically check GPU activity for detecting hangs. WARNING: Disabling this can cause system wide hangs. (default: true) (bool)
enable_ppgtt:Override PPGTT usage. (-1=auto [default], 0=disabled, 1=aliasing, 2=full, 3=full with extended address space) (int)
enable_execlists:Override execlists usage. (-1=auto [default], 0=disabled, 1=enabled) (int)
enable_psr:Enable PSR (0=disabled, 1=enabled - link mode chosen per-platform, 2=force link-standby mode, 3=force link-off mode) Default: -1 (use per-chip default) (int)
alpha_support:Enable alpha quality driver support for latest hardware. See also CONFIG_DRM_I915_ALPHA_SUPPORT. (bool)
disable_power_well:Disable display power wells when possible (-1=auto [default], 0=power wells always on, 1=power wells disabled when possible) (int)
enable_ips:Enable IPS (default: true) (int)
fastboot:Try to skip unnecessary mode sets at boot time (default: false) (bool)
prefault_disable:Disable page prefaulting for pread/pwrite/reloc (default:false). For developers only. (bool)
load_detect_test:Force-enable the VGA load detect code for testing (default:false). For developers only. (bool)
force_reset_modeset_test:Force a modeset during gpu reset for testing (default:false). For developers only. (bool)
invert_brightness:Invert backlight brightness (-1 force normal, 0 machine defaults, 1 force inversion), please report PCI device ID, subsystem vendor and subsystem device ID to dri-devel@lists.freedesktop.org, if your machine needs it. It will then be included in an upcoming module version. (int)
disable_display:Disable display (default: false) (bool)
enable_cmd_parser:Enable command parsing (true=enabled [default], false=disabled) (bool)
use_mmio_flip:use MMIO flips (-1=never, 0=driver discretion [default], 1=always) (int)
mmio_debug:Enable the MMIO debug code for the first N failures (default: off). This may negatively affect performance. (int)
verbose_state_checks:Enable verbose logs (ie. WARN_ON()) in case of unexpected hw state conditions. (bool)
nuclear_pageflip:Force enable atomic functionality on platforms that don't have full support yet. (bool)
edp_vswing:Ignore/Override vswing pre-emph table selection from VBT (0=use value from vbt [default], 1=low power swing(200mV),2=default swing(400mV)) (int)
enable_guc_loading:Enable GuC firmware loading (-1=auto, 0=never [default], 1=if available, 2=required) (int)
enable_guc_submission:Enable GuC submission (-1=auto, 0=never [default], 1=if available, 2=required) (int)
guc_log_level:GuC firmware logging level (-1:disabled (default), 0-3:enabled) (int)
guc_firmware_path:GuC firmware path to use instead of the default one (charp)
huc_firmware_path:HuC firmware path to use instead of the default one (charp)
enable_dp_mst:Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true) (bool)
inject_load_failure:Force an error after a number of failure check points (0:disabled (default), N:force failure at the Nth failure check point) (uint)
enable_dpcd_backlight:Enable support for DPCD backlight control (default:false) (bool)
enable_gvt:Enable support for Intel GVT-g graphics virtualization host support(default:false) (bool)

[jlittle]

echo -n 0 > /sys/module/i915/parameters/enable_rc6

That’s because the /sys dir is owned by root and you need to use sudo in front of it to execute that command.

sudo won't do the trick here:

$ sudo echo -n 0 > /sys/module/i915/parameters/enable_rc6
bash: /sys/module/i915/parameters/enable_rc6: Permission denied

(Perhaps this happened to the OP). This is because redirections (that's the ">") are done by the shell before the command is run. An often-suggested way to workaround this is to use tee -a :

$ echo -n 0 | sudo tee -a /sys/module/i915/parameters/enable_rc6

More directly, less hacky, but subject to quoting complications:

$ sudo bash -c 'echo -n 0 > /sys/module/i915/parameters/enable_rc6'

[claydoh]

Yes creating a config file in /etc/modprobe.d is the way to go. I just hadn't looked into it yet for specifics. Darn day and night job(s) lol.

I still think that disabling rc6 may not be useful for this hardware, so info and links to whatever source provided direction to do this might be helpful.


Sent from my LG-H931 using Tapatalk

[GreyGeek]

Random crashes, system freezes

Yes creating a config file in /etc/modprobe.d is the way to go. I just hadn't looked into it yet for specifics. Darn day and night job(s) lol.

I still think that disabling rc6 may not be useful for this hardware, so info and links to whatever source provided direction to do this might be helpful.


Sent from my LG-H931 using Tapatalk

Ya, rc6 may not be helpful, but the article I found that in listed 3-4 other Params that could be modified to eliminate freezes.

Searching on the echo command will find it.

[edugs]

That’s because the /sys dir is owned by root and you need to use sudo in front of it to execute that command. My fault for assuming you knew that.

I tried with root user. I am spanish sysadmin, level LPIC-2 more or less, but my experience is limited when something fails,.. like this.

I'm testing with the follow changes made.

vim /etc/default/grub
change the follow line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=1"

update-grub

and

apt remove thermald

Thank everybody. I will tell you how i go..
Thank you so much !!!

After longtime the system come back to freeze, I was listening music, the computer was longtime without touch, and the music stopped and the system crashed again.

[Ibrahim AdDandan]

echo -n 0 > /sys/module/i915/parameters/enable_rc6
*might* even change it until your next boot up.

bash: /sys/module/i915/parameters/enable_rc6: Permission denied
I appreciate your help.
first I think it an intel baytrail problem and try the suggested fixes, it's work properly for a while (3 days) but when try to download something it froze again!