[gentoo-user] new install for a new mainboard?

[gentoo-user] new install for a new mainboard?

[n952162]

I need a new mainboard.  What will happen if I boot my existing system
on it?

If it would come up, what would need to be (re)emerged, as a minimum?

TIA

Re: [gentoo-user] new install for a new mainboard?

[Matt Connell (Gmail)]

On Thu, 2020-12-10 at 16:23 +0100, n952162 wrote:
> What will happen if I boot my existing system on it?

Best case, it boots and has some minor issues to work through.

Worst case, it doesn't boot at all.

> If it would come up, what would need to be (re)emerged, as a minimum?

If you're building a kernel yourself from gentoo-sources, you'll most
likely need to review that kernel configuration and add support for new
hardware, optionally disabling support for old hardware.

Re: [gentoo-user] new install for a new mainboard?

[J. Roeleveld]

On Thursday, December 10, 2020 4:23:09 PM CET n952162 wrote:
> I need a new mainboard.  What will happen if I boot my existing system
> on it?
> 
> If it would come up, what would need to be (re)emerged, as a minimum?
> 
> TIA

Unless you really reduced the drivers available on your system or you're going 
to a lesser system (64 -> 32bit, or something like that), I would expect the 
system to simply boot.
If not, you only need a live-cd/usb/... and rebuild the kernel and any drivers 
your new system needs.

It's not MS Windows that might try to load incompatible drivers and ends up 
with a blue-screen.

Personally, however, I tend to use a new system as an excuse to clean up my 
install and start from scratch. Especially as I always tend to pass my old 
system on to a family member or friend.

Re: [gentoo-user] new install for a new mainboard?

[Matt Connell (Gmail)]

On Thu, 2020-12-10 at 16:49 +0100, J. Roeleveld wrote:
> I tend to use a new system as an excuse to clean up my install and start from scratch.

Same here.  Especially because I only upgrade workstations every 6-8
years.

I'll keep my world file and cherry-pick stuff from /etc/portage but
laregely just rebuild anew.

RE: [gentoo-user] new install for a new mainboard?

[Raffaele BELARDI]

> -----Original Message-----
> From: n952162 <n952162@web.de>
> Sent: Thursday, December 10, 2020 16:23
> To: gentoo-user@lists.gentoo.org
> Subject: [gentoo-user] new install for a new mainboard?
> 
> I need a new mainboard.  What will happen if I boot my existing system on it?
> 
> If it would come up, what would need to be (re)emerged, as a minimum?

Before switching to the new board I'd check the USB controller and possibly the video controller of the new board and if required build a kernel with those modules ready for the swap. Other than that you might want to check that both mainboards are configured for the same boot system (UEFI vs MBR).

You might get a kernel panic if you don't arrange the SATA cables as they were on the old board - unless you were already using UUID or similar in the bootloader.

Re: [gentoo-user] new install for a new mainboard?

[Rich Freeman]

On Thu, Dec 10, 2020 at 10:23 AM n952162 <n952162@web.de> wrote:
>
> I need a new mainboard.  What will happen if I boot my existing system
> on it?

Is the CPU going to be the same?  The responses already cover the
mainboard itself well.  If the CPU could change then you need to check
your -march in CFLAGS for compatibility (if you set it) and
potentially rebuild anything you don't want to break.

-- 
Rich

Re: [gentoo-user] new install for a new mainboard?

[n952162]

On 12/10/20 7:18 PM, Rich Freeman wrote:
> On Thu, Dec 10, 2020 at 10:23 AM n952162 <n952162@web.de> wrote:
>> I need a new mainboard.  What will happen if I boot my existing system
>> on it?
> Is the CPU going to be the same?  The responses already cover the
> mainboard itself well.  If the CPU could change then you need to check
> your -march in CFLAGS for compatibility (if you set it) and
> potentially rebuild anything you don't want to break.
>

How would I do that?  Would I have to set up a cross-compiler toolchain?

Re: [gentoo-user] new install for a new mainboard?

[Rich Freeman]

On Thu, Dec 10, 2020 at 4:18 PM n952162 <n952162@web.de> wrote:
>
> On 12/10/20 7:18 PM, Rich Freeman wrote:
> > On Thu, Dec 10, 2020 at 10:23 AM n952162 <n952162@web.de> wrote:
> >> I need a new mainboard.  What will happen if I boot my existing system
> >> on it?
> > Is the CPU going to be the same?  The responses already cover the
> > mainboard itself well.  If the CPU could change then you need to check
> > your -march in CFLAGS for compatibility (if you set it) and
> > potentially rebuild anything you don't want to break.
> >
>
> How would I do that?  Would I have to set up a cross-compiler toolchain?

Nope, just remove -march from your CFLAGS (maybe change it to -mtune)
and emerge -e @world (or @system if you don't care if non-system
packages are broken on the new system).

It is only necessary if you're switching CPUs.  If you're using -march
then your binaries are not guaranteed to run on ANY CPU other than the
one specified, and you'd be surprised how non-backwards-compatible
CPUs can be.  With gcc the -march option tells the compiler that it
can use any instruction it can to optimize things, including ones that
are very uncommon on other CPU models.  -mtune makes optimizations but
the code will run on any CPU for that architecture.

You can try to find a least-common-denominator CPU but it usually
isn't worth the hassle.

-- 
Rich

[gentoo-user] Re: new install for a new mainboard?

[Grant Edwards]

On 2020-12-10, n952162 <n952162@web.de> wrote:
> I need a new mainboard.  What will happen if I boot my existing system
> on it?

It depends on how "alike" your new and old mainboard are.

Everything might work 100%, or it might crash in the very early stages
of the kernel starting, or anything in-between.


> If it would come up, what would need to be (re)emerged, as a
> minimum?

The minimum would be "nothing".

--
Grant

[gentoo-user] Re: new install for a new mainboard?

[Grant Edwards]

On 2020-12-10, J. Roeleveld <joost@antarean.org> wrote:
> On Thursday, December 10, 2020 4:23:09 PM CET n952162 wrote:
>> I need a new mainboard.  What will happen if I boot my existing system
>> on it?
>> 
>> If it would come up, what would need to be (re)emerged, as a minimum?
>> 
>> TIA
>
> Unless you really reduced the drivers available on your system or
> you're going to a lesser system (64 -> 32bit, or something like
> that), I would expect the system to simply boot.

Many of us do "reduce the drivers availabing" to match just the
hardware in our system.

> If not, you only need a live-cd/usb/... and rebuild the kernel and
> any drivers your new system needs.

> It's not MS Windows that might try to load incompatible drivers and
> ends up with a blue-screen.

Well, the screen doesn't turn blue, but it's possible the kernel won't
even boot.

--
Grant

Re: [gentoo-user] new install for a new mainboard?

[Miles Malone]

On Fri, 11 Dec 2020 at 01:49, J. Roeleveld <joost@antarean.org> wrote:
>
>
> Personally, however, I tend to use a new system as an excuse to clean up my
> install and start from scratch. Especially as I always tend to pass my old
> system on to a family member or friend.
>

It's also an excellent opportunity to do a once in five year git
commit of all your dotfiles :)

Re: [gentoo-user] new install for a new mainboard?

[n952162]

Thank you (all).

On 12/10/20 10:53 PM, Rich Freeman wrote:
> On Thu, Dec 10, 2020 at 4:18 PM n952162 <n952162@web.de> wrote:
>> On 12/10/20 7:18 PM, Rich Freeman wrote:
>>> On Thu, Dec 10, 2020 at 10:23 AM n952162 <n952162@web.de> wrote:
>>>> I need a new mainboard.  What will happen if I boot my existing system
>>>> on it?
>>> Is the CPU going to be the same?  The responses already cover the
>>> mainboard itself well.  If the CPU could change then you need to check
>>> your -march in CFLAGS for compatibility (if you set it) and
>>> potentially rebuild anything you don't want to break.
>>>
>> How would I do that?  Would I have to set up a cross-compiler toolchain?
> Nope, just remove -march from your CFLAGS (maybe change it to -mtune)
> and emerge -e @world (or @system if you don't care if non-system
> packages are broken on the new system).
>
> It is only necessary if you're switching CPUs.  If you're using -march
> then your binaries are not guaranteed to run on ANY CPU other than the
> one specified, and you'd be surprised how non-backwards-compatible
> CPUs can be.  With gcc the -march option tells the compiler that it
> can use any instruction it can to optimize things, including ones that
> are very uncommon on other CPU models.  -mtune makes optimizations but
> the code will run on any CPU for that architecture.
>
> You can try to find a least-common-denominator CPU but it usually
> isn't worth the hassle.
>

Re: [gentoo-user] new install for a new mainboard?

[antlists]

On 10/12/2020 21:18, n952162 wrote:
> 
> On 12/10/20 7:18 PM, Rich Freeman wrote:
>> On Thu, Dec 10, 2020 at 10:23 AM n952162 <n952162@web.de> wrote:
>>> I need a new mainboard.  What will happen if I boot my existing system
>>> on it?
>> Is the CPU going to be the same?  The responses already cover the
>> mainboard itself well.  If the CPU could change then you need to check
>> your -march in CFLAGS for compatibility (if you set it) and
>> potentially rebuild anything you don't want to break.
>>
> 
> How would I do that?  Would I have to set up a cross-compiler toolchain?
> 
> 
I don't remember the details, but what I'd do is set the CPU to 
something basic like x86_64. Then do an "emerge -e system", so at least 
enough is there to guarantee your system will boot.

Then, if the new system does fail to get beyond the basic command line, 
you can change the CPU back to native, do an "emerge -e world", and you 
should have your system back.

Bit of a long-winded hassle, but it should work ...

Cheers,
Wol