[bug#34758,2/4] gnu: Add vhba.

* gnu/packages/cdrom.scm (vhba): New variable.
---
 gnu/packages/cdrom.scm | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Pierre Neidhardt <mail@ambrevar.xyz> skribis:

> * gnu/packages/cdrom.scm (vhba): New variable.

[...]

> +       (modify-phases %standard-phases
> +         ;; TODO: Compress kernel modules?
> +         ;; TODO: Build does not work because it needs the Makefile in
> +         ;; /lib/modules/$(KERNELRELEASE)/build which we don't ship in Guix.
> +         (delete 'configure))))

So it doesn’t build, right?  In that case I’d rather not add it.  :-)

It’s true that /build is a dangling link:

--8<---------------cut here---------------start------------->8---
$ readlink $(guix build linux-libre)/lib/modules/5.0.2-gnu/build
/tmp/guix-build-linux-libre-5.0.2.drv-0/linux-5.0.2
--8<---------------cut here---------------end--------------->8---

Ludo’.

I should have explained a little bit more: the whole patchset makes no
sense (beside libmirage) without this kernel module.  CDEmu needs it or
it won't run.

This raises a general, important question: how do we build kernel
modules on guix?  At the moment, it seems that it's only possible by
re-building the kernel.

I suggest we add a "build" output to the kernel  that can be used as an
input to build kernel modules.  Maybe I should should an email to
guix-devel to ask for more opinions / advice.

Also see my other email from Tue, 05 Mar 2019 18:44:25 +0100 in this thread.

Hello,

Pierre Neidhardt <mail@ambrevar.xyz> skribis:

> I should have explained a little bit more: the whole patchset makes no
> sense (beside libmirage) without this kernel module.  CDEmu needs it or
> it won't run.

Oh I see, I didn’t know that.

> This raises a general, important question: how do we build kernel
> modules on guix?  At the moment, it seems that it's only possible by
> re-building the kernel.

… or maybe just unpacking the kernel source so you have the makefile
snippet around?  Perhaps that’s enough?

I’m generally dubious about out-of-tree modules.  Given the way kernel
development works, we’re often talking about modules of poor quality, or
proprietary modules.  Do you know the reason this one is not in the main
tree?

> I suggest we add a "build" output to the kernel  that can be used as an
> input to build kernel modules.  Maybe I should should an email to
> guix-devel to ask for more opinions / advice. 

Yes, sounds like a good idea.

Thanks,
Ludo’.

Ludovic Courtès <ludo@gnu.org> writes:

>> This raises a general, important question: how do we build kernel
>> modules on guix?  At the moment, it seems that it's only possible by
>> re-building the kernel.
>
> … or maybe just unpacking the kernel source so you have the makefile
> snippet around?  Perhaps that’s enough?

Nope, because we need the "build" folder which is only available after
building the kernel.  Re-building the kernel just to build a module
sounds like a waste of time :p

> I’m generally dubious about out-of-tree modules.  Given the way kernel
> development works, we’re often talking about modules of poor quality, or
> proprietary modules.  Do you know the reason this one is not in the main
> tree?

I don't.  I'll investigate a bit.

Anyways, I think it's nice as a _free software distribution_ to make it
accessible to the user to build custom modules.

>> I suggest we add a "build" output to the kernel  that can be used as an
>> input to build kernel modules.  Maybe I should should an email to
>> guix-devel to ask for more opinions / advice. 
>
> Yes, sounds like a good idea.

Will do!

Hi,

Pierre Neidhardt <mail@ambrevar.xyz> skribis:

> Ludovic Courtès <ludo@gnu.org> writes:
>
>>> This raises a general, important question: how do we build kernel
>>> modules on guix?  At the moment, it seems that it's only possible by
>>> re-building the kernel.
>>
>> … or maybe just unpacking the kernel source so you have the makefile
>> snippet around?  Perhaps that’s enough?
>
> Nope, because we need the "build" folder which is only available after
> building the kernel.  Re-building the kernel just to build a module
> sounds like a waste of time :p

I wasn’t suggesting a kernel rebuild.  I thought that perhaps it’s
enough to use the makefiles and build machinery directly from the kernel
source tree, without rebuilding the kernel itself.  Dunno if that’s possible.

>> I’m generally dubious about out-of-tree modules.  Given the way kernel
>> development works, we’re often talking about modules of poor quality, or
>> proprietary modules.  Do you know the reason this one is not in the main
>> tree?
>
> I don't.  I'll investigate a bit.
>
> Anyways, I think it's nice as a _free software distribution_ to make it
> accessible to the user to build custom modules.

I agree, no argument here.  :-)

Thanks,
Ludo’.