On 2020-01-14 07:10, Mauricio Tavares wrote:
On Mon, Jan 13, 2020 at 5:46 PM Ed Greshko ed.greshko@greshko.com wrote:
On 2020-01-14 06:01, Mauricio Tavares wrote:
So I want to add a few options to the kernel (say iommu support). I have been told before to avoid using grub2-mkconfig because it would apply the changes to all currently available (to boot from) boot kernels. Instead, I should edit just the latest kernel entry in the grub.cfg file, adding the option to the line starting with linux16. This way, if it went boink, all I had to do is reboot, pick another kernel from the grub menu and off I went. And, it seems that every future kernel upgrade would incorporate this change.
Is that accurate or is there a cleaner way to do the same while still leaving me the option to go back to the grub menu?
Do you wish to try out some options without make a permanent change?
Assuming your using Fedora Workstation, which unlike other spins, doesn't present the list of kernels to boot. You'd just hit the "escape" key when booting. Then you'd see the list of kernels. Hit "e" to edit. Go to the linux line, add the parameters and then Ctrl-x to continue the boot.
Those changes are temporary.
If all works as you'd like, then you could make them permanent.
Thank you for your reply but it seems I failed to properlyexplain myself. I want to ensure my changes only affect the latest kernel (and future kernels) as listed in the grub menu. I was not aware there is a version of fedora which would not list available kernels; if there is I would rather not use such version. The fedora version I use does provide me with a proper grub menu hence me describing that in the problem statement.
When you escape into the menu you'll most likely see 3 (or 4 if there is a rescue) kernel. The one at the top is the most recent, default, kernel.
Your changes will only affect the kernel that you pick to edit, the most recent/default.
The changes will only be for the one boot.
If you boot again, the changes will have to be made again. That is what I meant by "temporary".
This, is good for "testing" should things go bonkers. You can reboot, the changes you made are gone. And you can continue as normal.
I should have indicated that, in my experience, that was a good way to test things with the least amount of pain should things go wrong. Then, after testing, make things permanent.