How do I REMOVE a video driver?

[taylorkh]

I have a Dell Precision T3620 workstation which is running CentOS 7.3. I am encountering a conflict between the Intel built in video driver and the Nvidia Quadro K620 card which I added to it. I installed kmod-nvidia from ElRepo and it seems to work OK. When I suspend and then resume the machine I see this message on the screen before the colored gui display loads

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[    1.130608] [drm:i915_gem_init_stolen [i915]] *ERROR* conflict detected with stolen region: [0xce000000 - 0xd0000000]

Is the Intel gpu disabled in BIOS? I have no idea. The wording in BIOS is bizarre to put it politely. Dell Premier Tech Support has been working for 3 weeks to answer that question for me.

This afternoon while taking my dog for our usual afternoon walk - a good time for thinking - it came to me that I might be better off to remove the Intel driver. That way it would not matter if the Intel graphics were enabled, disabled, active, inactive or radioactive. In further support of this idea...

I purchase an identical machine to this a few weeks ago. I included an Nvidia Quadro K420 in the original configuration. I had it almost ready to replace my old CentOS 6 machine when I came across a BIOS corruption. Long story short after 4 hours working with Tech Support they had managed to brick the machine. Sent it back and order the one I currently have.

On this second machine I decided to try the Intel build in graphics to see if they would meet my needs. I installed CentOS 7.3. The Intel graphics did not suffice so I added the K620 card.

CentOS was installed onto the FIRST machine with the Nvidia card installed. Perhaps the install saw that and did not bother with the Intel graphics. That machine did not exhibit the error I am seeing on the second machine. The question is... How do I remove the Intel driver?

Here are the results of my investigation so far.

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[root@taylor20 Desktop]# lspci | grep Intel

00:02.0 Display controller: Intel Corporation HD Graphics 530 (rev 06)

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[root@taylor20 Desktop]# less /proc/modules 
 
 (I found the following lines of interest)
 
nvidia_drm 53080 1 - Live 0xffffffffa01cd000 (POE)
nvidia_modeset 790274 4 nvidia_drm, Live 0xffffffffa0fd4000 (POE)
i915 1307079 2 - Live 0xffffffffa0e5c000
nvidia 12145802 70 nvidia_modeset, Live 0xffffffffa01ea000 (POE)
crct10dif_pclmul 14289 1 - Live 0xffffffffa01c8000
crct10dif_common 12595 3 crc_t10dif,crct10dif_generic,crct10dif_pclmul, Live 0xf
fffffffa0121000

video 24400 1 i915, Live 0xffffffffa0018000

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[root@taylor20 Desktop]# lsmod

 (I found the following lines of interest)
 
nvidia_drm             53080  1 
nvidia_modeset        790274  4 nvidia_drm
i915                 1307079  2 
nvidia              12145802  70 nvidia_modeset

i2c_hid                18821  0 
i2c_core               40756  7 drm,i915,i2c_i801,i2c_hid,drm_kms_helper,i2c_algo_bit,nvidia

I looks to me like this "i915" driver is the thing I want to zap but I have no idea how. yum search i915 does not find anything so I am guessing that the driver is part of the base installation, not an addon package. Can someone help?

TIA,

Ken

[taylorkh]

For my next trick I decided to try and BLACKLIST the offending driver (if I have in fact identified it correctly). I tried creating /etc/modprobe.d/blacklist.conf containing the line

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blacklist i915

I then rebooted and used the log file viewer to examine dmesg. No change. I deleted the blacklist.conf file and attempted to add the blacklist option to grub. I tried a couple of syntax variations. No luck. Here are the Kernel command lines from dmesg for my two attempts

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[    0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.10.0-514.10.2.el7.x86_64 root=UUID=3f9a12d7-3362-4273-90e4-a5cfae68a751 ro crashkernel=auto rhgb quiet nouveau.modeset=0 rd.driver.blacklist=nouveau blacklist=i915

changed to rd.driver.blacklist=i915 to match the nouveau blacklist entry

[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-3.10.0-514.10.2.el7.x86_64 root=UUID=3f9a12d7-3362-4273-90e4-a5cfae68a751 ro crashkernel=auto rhgb quiet nouveau.modeset=0 rd.driver.blacklist=nouveau rd.driver.blacklist=i915

I still get the "conflict detected with stolen region" message.

Ken

[TrevorH]

You'll need to rebuild the initramfs to include your new blacklist file.

[taylorkh]

Thanks TrevorH,

I did perform the grub2 updating process after making the grub option change

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grub2-mkconfig -o /boot/grub2/grub.cfg (replaces update-grub)

I will have to look into how to do the rebuild process. I think I may also do a quick install of CentOS onto a test drive with the Nvidia card installed - just to test my theory that an extraneous driver is causing my issues. I will update this thread with my findings.

Thanks again,

Ken

[taylorkh]

Update: I am still researching how to rebuild the initramfs. In the interim I installed CentOS 7 on a temporary hard drive. In this case I followed this sceme:

1 - Install CentOS 7 minimal & yum update
2 - Install yum-priorities, elrepo and epel repos
3 - Set CentOS Base and CR to priority=1; elreop priority=5, epel priority=10
4 - yum groupinstall "X Window system" mate-desktop-environment
5 - systemctl set-default graphical.target
rm '/etc/systemd/system/default.target'
ln -s '/usr/lib/systemd/system/graphical.target' '/etc/systemd/system
6 - reboot
7 - yum install nvidia-detect and run nvidia-detect It tells me kmod-nvidia as expected.
8 - Tried to install kmod-nvidia

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[root@t20 Desktop]# yum install kmod-nvidia
Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
 * base: centos.mirror.nac.net
 * elrepo: iad.mirror.rackspace.com
 * epel: mirror.us.leaseweb.net
 * extras: repos-va.psychz.net
 * updates: ftp.linux.ncsu.edu
268 packages excluded due to repository priority protections
Resolving Dependencies
--> Running transaction check
---> Package kmod-nvidia.x86_64 0:375.39-2.el7.elrepo will be installed
--> Processing Dependency: nvidia-x11-drv = 375.39 for package: kmod-nvidia-375.39-2.el7.elrepo.x86_64
--> Running transaction check
---> Package nvidia-x11-drv.x86_64 0:375.39-1.el7.elrepo will be installed
--> Processing Dependency: yum-plugin-nvidia >= 1.0.2 for package: nvidia-x11-drv-375.39-1.el7.elrepo.x86_64
--> Running transaction check
---> Package yum-plugin-nvidia.noarch 0:1.0.2-1.el7.elrepo will be installed
--> Processing Conflict: nvidia-x11-drv-340xx-340.102-1.el7.elrepo.x86_64 conflicts nvidia-x11-drv
--> Processing Conflict: nvidia-x11-drv-375.39-1.el7.elrepo.x86_64 conflicts nvidia-x11-drv-340xx
--> Finished Dependency Resolution
Error: nvidia-x11-drv-340xx conflicts with nvidia-x11-drv-375.39-1.el7.elrepo.x86_64
Error: nvidia-x11-drv conflicts with nvidia-x11-drv-340xx-340.102-1.el7.elrepo.x86_64
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest

I noted that nvidia-settings is installed so I guess the nvidia driver got installed during the groupinstall process. I generally do not add elrepo until after I have the gui up and running. The good news is I do not see the i915 stolen conflict messages any more. Let me get to work on that initramfs. I have never done that before.

Ken

[taylorkh]

Another update:

I created /etc/modprobe.d/blacklist.conf containing one line

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blacklist i915

I then regenerated initramfs as follows

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dracut -f /boot/initramfs-3.10.0-514.10.2.el7.x86_64.img 3.10.0-514.10.2.el7.x86_64

The computer rebooted fine. However, I still see the 1915 stolen conflict error. Can someone point to what I have done wrong? Do I perhaps not have the correct name of the driver which I am trying to blacklist?

TIA,

Ken