On 5/14/2021 5:15 PM, John Blinka wrote:
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On Fri, May 14, 2021 at 2:36 AM John Covici <cov...@ccs.covici.com
<mailto:cov...@ccs.covici.com>> wrote:
I would look in the grub.cfg and give us exactly what is in the stanza
you are using, including where it thinks the root file system is,
etc. Also, see if there is any genkernel option to get some debugging
info out of the initrd, I know using dracut you can get breakpoints
during the process and see how its doing.
Tried dracut. No change.
Added the kernel command line debug options (#3 in “Identifying your
problem area” in ‘man dracut’). No change.
Feeling peevish, I made a file of random junk using dd if=/dev/random
of=initrd.img count=4096. Then supplied that pile of junk as the
initrd. Again, no change.
Then I supplied a nonexistent file name (xxx.img) as the initrd. This
time I got a complaint:
error: file ‘/xxx.img’ not found.
Press any key to continue...
So, it’s getting as far as wanting to read the initrd, and is smart
enough to tell whether the specified initrd actually exists on the
specified boot partition. But it can’t actually be doing anything
with the initrd, or it would have objected to the random junk I fed it.
From https://en.m.wikipedia.org/wiki/Initial_ramdisk#Implementation
<https://en.m.wikipedia.org/wiki/Initial_ramdisk#Implementation>, it
appears that grub is in charge of loading both linux and the initrd
into memory, then handing execution over to linux along with a pointer
to the memory location of the initrd.
I’ve observed that that no booting output comes out of linux, nor any
complaints from linux about the nonsense contents I fed it from the
random initrd I built. That suggests to me that grub has failed to
load linux and/or the initrd into memory, or that it's failed to hand
execution control to linux.
Next step: learned how to run an interactive grub2 command shell.
With full debugging turned on, it looks like grub2 can load the kernel
image, and it looks like it loads the initrd as well. At least there
are no complaints and the reported initrd size looks correct.
But when I issue the boot command, grub2 issues a handful of mallocs
and does a little token parsing, and then just stops...
So it appears that the boot problem arises right around the handoff
from grub2 to linux. Don’t know whether grub2 or linux has failed. I
don’t know how to get either one to tell me more.
John
This is likely not your issue with an integrated Intel GPU, but I was
building a new system recently with UEFI, ASUS ROG mobo, and nvidia GPU
and had this same issue.
Surprisingly, this turned out to require me to set the simple
framebuffer support in the kernel config (I also set the UEFI
framebuffer support) or else I would get no screen output after the
loading initial ramdisk... message.
Just something I ran into for the first time ever recently
Todd
