Xen and all_video.mod

Xen and all_video.mod

[Colin Watson]

Current master fails like this when configured with --with-platform=xen
and using binutils 2.27:

  TARGET_OBJ2ELF= sh genmod.sh moddep.lst all_video.module build-grub-module-verifier all_video.mod
  build-grub-module-verifier: error: no symbol table and no .moddeps section.
  Makefile:42584: recipe for target 'all_video.mod' failed

There's no video driver configured for Xen in
grub-core/Makefile.core.def, so this makes a certain amount of sense:
it's an empty module with no dependencies, which is what
67dba97e4598eaf2deb14da044fbfb1c119cf76f purports to prevent.  On the
other hand, that does make Xen unbuildable at least with some binutils
versions (2.26.1 seems to work fine; more specifically, I can build
--with-platform=xen on Ubuntu xenial but not on Debian unstable).  I
considered just adding the cirrus driver for Xen to pacify this, but
that uses PCI symbols that aren't built for Xen at the moment.

What's the best answer here?  Is there some reasonable way to weaken
this test so that this module is allowed to be useless on this platform?

Thanks,

-- 
Colin Watson                                       [cjwatson@ubuntu.com]

Re: Xen and all_video.mod

[Andrei Borzenkov]

19.09.2016 20:28, Colin Watson пишет:
> Current master fails like this when configured with --with-platform=xen
> and using binutils 2.27:
> 
>   TARGET_OBJ2ELF= sh genmod.sh moddep.lst all_video.module build-grub-module-verifier all_video.mod
>   build-grub-module-verifier: error: no symbol table and no .moddeps section.
>   Makefile:42584: recipe for target 'all_video.mod' failed
> 
> There's no video driver configured for Xen in
> grub-core/Makefile.core.def, so this makes a certain amount of sense:
> it's an empty module with no dependencies, which is what
> 67dba97e4598eaf2deb14da044fbfb1c119cf76f purports to prevent.  On the
> other hand, that does make Xen unbuildable at least with some binutils
> versions (2.26.1 seems to work fine; more specifically, I can build
> --with-platform=xen on Ubuntu xenial but not on Debian unstable).  I
> considered just adding the cirrus driver for Xen to pacify this, but
> that uses PCI symbols that aren't built for Xen at the moment.
> 
> What's the best answer here?  Is there some reasonable way to weaken
> this test so that this module is allowed to be useless on this platform?
> 

Yes, that's what openSUSE is using currently, see also
http://savannah.gnu.org/bugs/?49012

I hoped there is some trick to skip building this module generically,
but then we also have potential issue with config scripts.

What about changing all_video to actually load modules at run time based
on video.lst? The code itself is trivial.