Re: [OE-core] [PATCH] linux-libc-headers: Check for asm/bpf_perf_event.h before multilibbing

["Adrian Bunk" <bunk@stusta.de>]

On Thu, May 28, 2020 at 10:38:15AM -0700, Andre McCurdy wrote:
> On Thu, May 28, 2020 at 6:39 AM Adrian Bunk <bunk@stusta.de> wrote:
> >
> > On Thu, May 28, 2020 at 02:20:02PM +0100, Richard Purdie wrote:
> > >
> > > Right, external toolchains I can understand having specific version
> > > requirements. What I don't really understand is external toolchains
> > > would come with their own headers in most cases I can think of?
> >
> > What I don't really understand is why kernel 4.1 was mentioned
> > in the submission.
> >
> > At kernel 4.1 times the latest gcc was gcc 5.
> >
> > gcc 5 is not even supported as host gcc in master,
> > and target builds are only tested with gcc 10.
> 
> Is that an argument that users with an older vendor kernel should not
> update to newer versions of OE? Or that OE should provide older
> versions of gcc (in addition to the default) in order to support older
> kernels?

It is an argument that ancient external toolchains will anyway not work.

> And where does it leave OLDEST_KERNEL (currently set to 3.2.0)?

OLDEST_KERNEL is just what is passed to glibc as lowest supported kernel,
other OE components might have higher version requirements.

> If even kernel 4.1 is too old to be used with OE master then
> OLDEST_KERNEL looks like it should be updated to avoid giving users
> with older kernels false hope.

linux-libc-headers are the headers used by the C library in the
toolchain, this is unrelated to the kernel running on the target.

cu
Adrian