How to configure workable kernel and not break it?

[znavko]

Hello dear forum members! My Portage emerged and successfully compiled kernel debian-sources-4.14.2-1 with no any question to me. I edited /etc/boot.conf, run boot-update and my grub booted automatically in my new kernel. Xorg, xdm, Slim, LXDE worked fine.

But today I tried to "root out" IPv6 support from my kernel just for trying to optimize something. I run

# cd /usr/src/linux
# genkernel --menuconfig all

switched off line "Networking ->IPv6 for RxRPC" and saved my config to without-ipv6.config. Exited menuconfig and genkernel continued to compile kernel with my new configurations.

But after reboot Xorg failed to start, cause "Screens not found". I rebooted to my old kernel debian-sources-4-8 everything is ok.

I want you to teach me use genkernel, cause it is the second time I use it and the second time my system boots into console mode.

Here it is the Xorg.log of failed kernel:

# cat /var/log/Xorg.0.log.old
[    17.347] 
X.Org X Server 1.19.3
Release Date: 2017-03-15
[    17.347] X Protocol Version 11, Revision 0
[    17.347] Build Operating System: Linux 4.9.47-std510-amd64 x86_64 Gentoo
[    17.347] Current Operating System: Linux localhost 4.14.2-1 #1 SMP Thu Jan 4 17:13:40 MSK 2018 x86_64
[    17.347] Kernel command line: BOOT_IMAGE=/kernel-debian-sources-x86_64-4.14.2-1 rootfstype=auto real_root=/dev/sda3 rootfstype=ext4
[    17.347] Build Date: 20 December 2017  06:37:50PM
[    17.347]  
[    17.347] Current version of pixman: 0.34.0
[    17.347] 	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
[    17.347] Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    17.347] (==) Log file: "/var/log/Xorg.0.log", Time: Fri Jan  5 15:14:33 2018
[    17.356] (==) Using config directory: "/etc/X11/xorg.conf.d"
[    17.356] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    17.358] (==) No Layout section.  Using the first Screen section.
[    17.358] (==) No screen section available. Using defaults.
[    17.358] (**) |-->Screen "Default Screen Section" (0)
[    17.358] (**) |   |-->Monitor "<default monitor>"
[    17.358] (==) No device specified for screen "Default Screen Section".
	Using the first device section listed.
[    17.358] (**) |   |-->Device "Intel Graphics"
[    17.358] (==) No monitor specified for screen "Default Screen Section".
	Using a default monitor configuration.
[    17.358] (==) Automatically adding devices
[    17.358] (==) Automatically enabling devices
[    17.358] (==) Automatically adding GPU devices
[    17.358] (==) Max clients allowed: 256, resource mask: 0x1fffff
[    17.366] (==) FontPath set to:
	/usr/share/fonts/misc/,
	/usr/share/fonts/TTF/,
	/usr/share/fonts/OTF/,
	/usr/share/fonts/Type1/,
	/usr/share/fonts/100dpi/,
	/usr/share/fonts/75dpi/
[    17.367] (==) ModulePath set to "/usr/lib64/xorg/modules"
[    17.367] (II) The server relies on udev to provide the list of input devices.
	If no devices become available, reconfigure udev or disable AutoAddDevices.
[    17.367] (II) Loader magic: 0x807c80
[    17.367] (II) Module ABI versions:
[    17.367] 	X.Org ANSI C Emulation: 0.4
[    17.367] 	X.Org Video Driver: 23.0
[    17.367] 	X.Org XInput driver : 24.1
[    17.367] 	X.Org Server Extension : 10.0
[    17.370] (--) PCI:*(0:0:2:0) 8086:0f31:17aa:3905 rev 14, Mem @ 0x90000000/4194304, 0x80000000/268435456, I/O @ 0x00002050/8, BIOS @ 0x????????/131072
[    17.370] (II) LoadModule: "glx"
[    17.377] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so
[    17.395] (II) Module glx: vendor="X.Org Foundation"
[    17.395] 	compiled for 1.19.3, module version = 1.0.0
[    17.395] 	ABI class: X.Org Server Extension, version 10.0
[    17.395] (II) LoadModule: "intel"
[    17.397] (II) Loading /usr/lib64/xorg/modules/drivers/intel_drv.so
[    17.401] (II) Module intel: vendor="X.Org Foundation"
[    17.401] 	compiled for 1.19.3, module version = 2.99.917
[    17.401] 	Module class: X.Org Video Driver
[    17.401] 	ABI class: X.Org Video Driver, version 23.0
[    17.401] (II) intel: Driver for Intel(R) Integrated Graphics Chipsets:
	i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G,
	915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM,
	Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33,
	GM45, 4 Series, G45/G43, Q45/Q43, G41, B43
[    17.401] (II) intel: Driver for Intel(R) HD Graphics
[    17.401] (II) intel: Driver for Intel(R) Iris(TM) Graphics
[    17.401] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics
[    17.401] (++) using VT number 7

[    17.411] (EE) No devices detected.
[    17.411] (EE) 
Fatal server error:
[    17.411] (EE) no screens found(EE) 
[    17.411] (EE) 
Please consult the The X.Org Foundation support 
	 at http://wiki.x.org
 for help. 
[    17.411] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[    17.411] (EE) 
[    17.416] (EE) Server terminated with error (1). Closing log file.

 

The configs with ipv6 were these:

# cat withuot-ipv6.config | grep IPV6
CONFIG_IPV6=m
CONFIG_IPV6_ROUTER_PREF=y
# CONFIG_IPV6_ROUTE_INFO is not set
# CONFIG_IPV6_OPTIMISTIC_DAD is not set
# CONFIG_IPV6_MIP6 is not set
# CONFIG_IPV6_ILA is not set
# CONFIG_IPV6_VTI is not set
CONFIG_IPV6_SIT=m
# CONFIG_IPV6_SIT_6RD is not set
CONFIG_IPV6_NDISC_NODETYPE=y
CONFIG_IPV6_TUNNEL=m
# CONFIG_IPV6_FOU is not set
# CONFIG_IPV6_FOU_TUNNEL is not set
# CONFIG_IPV6_MULTIPLE_TABLES is not set
# CONFIG_IPV6_MROUTE is not set
# CONFIG_IPV6_SEG6_LWTUNNEL is not set
# CONFIG_IPV6_SEG6_HMAC is not set
CONFIG_NF_DEFRAG_IPV6=m
CONFIG_NF_CONNTRACK_IPV6=m
# CONFIG_NF_SOCKET_IPV6 is not set
# CONFIG_NF_DUP_IPV6 is not set
CONFIG_NF_REJECT_IPV6=m
# CONFIG_NF_LOG_IPV6 is not set
# CONFIG_NF_NAT_IPV6 is not set
CONFIG_IP6_NF_MATCH_IPV6HEADER=m
# CONFIG_AF_RXRPC_IPV6 is not set

 

How to recompile my kernel and run Xorg if I have old config saved automatically in /usr/src/linux-debian-sources-4.14.2

# ls -la /usr/src/linux
....
-rw-r--r--   1 root root        59 ноя 24 10:37 .cocciconfig
-rw-r--r--   1 root root    197345 янв  5 15:37 .config
-rw-r--r--   1 root root    151394 янв  4 16:44 .config--2018-01-04--16-44-29.bak
-rw-r--r--   1 root root    197345 янв  5 13:56 .config--2018-01-05--13-56-08.bak  - this is workable  
-rw-r--r--   1 root root    130817 янв  5 15:35 .config--2018-01-05--15-35-18.bak
-rw-r--r--   1 root root    197345 янв  5 15:36 .config.old
....

 

What was wrong?

[znavko]

I run `genkernel --menuconfig all` and then load saved workable config. without any edition exited, genkernel continued to compile. now my funtoo debian-sources-4.14 boot ok.

 

[znavko]

I think emerge uses workable configurations. May be every time I want to recompile, needs to load saved config??? But this line 'Copy configurations if you have previous configurations to copy: ' here https://www.funtoo.org/Building_a_Kernel_from_Source is hard for understanding.

[palica]

so there is a difference between using emerge debian-sources with USE=binary -> that will build a kernel for you using debian scripts and almost everything will work.

compared to using genkernel where you need to supply the right config. Best way is to save current kernel config in a file and load that in genkernel. Menuconfig, ncfongi all have a way of loading a config file.

so what went wrong is probably that the genkernel config was not complete and didn't include graphic drivers.