Cannot boot laptop due to video driver

[Robin Laing]

On 2015-01-17 02:25, poma wrote:
> On 17.01.2015 05:51, Robin Laing wrote:
>> On 2015-01-16 00:55, poma wrote:
>>> On 16.01.2015 07:20, Robin Laing wrote:
>>>> Hello,
>>>>
>>>> I am trying to help my child whom is across the country repair their
>>>> laptop after installing the wrong video driver.  They can boot into
>>>> emergency mode but not any of the other kernels.
>>>>
>>>> During booting into the system, the boot process stops close to the
>>>> point of starting KDM.
>>>
>>>
>>> It is *boot*-ing OK, only the *init*-ialization of the userspace service - in your case display/login manager(KDM), doesn't work.
>>> KDM depends on the X server, which in turn depends on functional X video module *and* kernel video module.
>>> You should deal with modules within 'multi-user.target'. i.e. non-graphical user environment and shouldn't touch the configuration of the boot loader, at all.
>>>
>>
>>
>> It was the wee hours of the morning for my child and I am not that
>> familiar with the new systemd commands and couldn't figure out how to
>> get into a single or multi-user with no X.  The boot process didn't
>> leave things at a terminal window or allow ctrl+alt+F{x} to work.
>> Basically it was reboot to do anything.
>>
>> Emergency mode didn't work as per the documentation with chroot and
>> being so late, it was easier to take sometime to read up on it.  The
>> laptop wasn't needed until Saturday.
>>
>> Some searching later and found that I was close last night, just didn't
>> know the correct services command to run.
>>
>> I think this would be beneficial in the Fedora documentation and I am
>> willing to write it for addition.
>>
>> What we ended up doing.
>>
>> 1.  On boot, we paused grub and in the edit mode added "single" to the
>> end of the "vmlinuz" line.
>> 	linux    /vmlinuz-3.17.7-300 ... single
>>
>> 2.  Once booted into emergency mode, entered the root password.
>>
>> 3.  Started Network Manager with
>> 	systemctl start NetworkManager.service
>>
>> This started the network but it wasn't working wireless or wired.  The
>> only wired connection was for a different network with a static IP and
>> different gateway IP.
>>
>> 4.  Listed the connections
>> 	nmcli  connection show
>>
>> 5.  Created a new network connection with
>> 	nmcli connection edit con-name <name of new connection>
>> where the ethernet port was used and ipv4 selected.  Saved on quit.
>>
>> 6.  Restarted Network Manager (not sure if this step was needed or not)
>> 	systemctl  restart NetworkManager.service
>>
>> 7.  On restart, Network Manager selected the wrong connection again.
>> Started the correct one.
>> 	nmcli  connection down id <wrong connection name>
>> 	nmcli connection up id <new connection name>
>>
>> 8.  Tested network connections to see if DHCP had worked and it did.  We
>> used ping tests to 8.8.8.8 (Google public name server) and ping
>> Google.ca for a DNS test.
>>
>> 9.  Use RPM to find the problem driver.
>> 	rpm -qa | grep nvidia
>>
>> 10. Used yum to erase the problem driver
>> 	yum erase <problem driver>
>>
>> 11. Rebooted
>> 	shutdown -r now
>>
>> And all is well on the reboot.
>>
>> I have to find time to learn systemd better.
>>
>> Hope this helps someone else.
>>
>> Robin
>>
>
> Before you begin to test a new video modules, it is recommended to do this:
> # systemctl set-default multi-user.target
>
> Switching from multi-user.target i.e. non-graphical user environment
> to graphical.target i.e. graphical user environment
> is done as follows:
> # systemctl isolate graphical.target
>
> After confirming the new configuration, you can return to graphical user environment:
> # systemctl set-default graphical.target
>
>
> In this way, complicated procedure you mentioned is unnecessary.
>
>

That is useful information.

I will pass it on to my child.

Thank you.