[SOLVED] Can't find root during boot

[matt_w]

TL:DR - genkernel did not compile with SCSI support so upon attempting to boot, the kernel could not find my hard drive. Rebuilding the kernel so that sata/scsi support was included solved the problem.

OP:

I'm thinking that the grub.cfg isn't lining up with what's in my /etc/fstab - I'm not sure how these are supposed to look in comparison to one another. If this isn't the problem, then genkernel might have missed some driver for my motherboard or something?

Relevant parts..

[eccerr0r]

My guess is that genkernel indeed is missing a driver for your motherboard.

What you need to look for in that big long grub.cfg is the "linux ..." statements such as

[Hu]

If you still need help, please post the last 20 lines of kernel output, ending where it says it cannot find the root device. That output can help us understand what steps succeeded and which step failed. That in turn will tell us which solutions are likely to apply.

[matt_w]

[eccerr0r]

Yeah, likely.

You can start up the "shell" and run "blkid" there and verify that you can't see the hard disk... I think the error means that it can't find the device versus can't mount due to missing filesystem driver but I'm not sure. If blkid reports your partition, then likely you don't have the filesystem driver in your initramfs or built into your kernel.

Now I have never used genkernel so I don't know what's involved, but posting the contents of your lspci might be helpful.
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

[matt_w]

[eccerr0r]

You should be able to, that's what I do, I don't use genkernel...

I'm surprised it omitted the AHCI drivers you need for your kernel. Unfortunately I don't know exactly what's needed to get that to build. It looks like genkernel using the --menuconfig option should give you that menuconfig that you're accustomed to seeing. Supposedly you can just use "make menuconfig" as usual and save the config, and then go back to genkernel and it will use that configuration too!

IMHO the only reason to use genkernel is for that initramfs if it's needed. I use a custom initramfs that I built a while ago and keep using it due to "not invented here syndrome" :( alas the Gentoo initramfs looks pretty full of features mine doesn't have.
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Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

[LIsLinuxIsSogood]

If the only problem seems to be the wrong UUID, have you attempted manually changing the boot option from Grub to load based on the device location in the form of root=/dev/sdx, which is something I seem to recall having to do numerous occasions with regards to UUID being a non-option under certain conditions, like in case you don't have an initramfs or as others have pointed out that gentoo's initramfs is unique and I don't know if it does the job of telling init where the filesystem is to be mounted, if I have that right. Try a few other boot lines, and then once you get it right that would be a good time to go back and discover which of the many boot parameters are acceptable to the different moving parts (there is hardware and software to be concerned with this one).

[eccerr0r]

Well, we have proven that the kernel did not load the right drivers since the blkid experiment in the initramfs failed to report his hard drive, so even if hardcoded /dev/sdXY were used, it will not work....

UUID and LABEL are supported by the genkernel initramfs as well as many other initramfs (dracut, and my homemade one). Without initramfs, only PARTUUID is usable. With a kernel lacking all the necessary drivers, none of these are usable :)
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

[matt_w]

Rebuilt the kernel manually - the system works!