On Fri, 18 Sep 2020 at 22:03, Nick Desaulniers [off-list ref] wrote:

On Wed, Sep 16, 2020 at 11:01 PM Ard Biesheuvel [off-list ref] wrote:

quoted

On Thu, 17 Sep 2020 at 00:25, Nick Desaulniers [off-list ref] wrote:

quoted

Also, it looks like the GCC build of milbeaut_m10v_defconfig fails to
boot for me in QEMU; so maybe not just a Clang bug (or maybe, more
than one bug).  (or maybe one of my command line params to QEMU is
wrong).

I understand that this is actually an existing issue in -next, but in
general, why would you expect to be able to boot
milbeaut_m10v_defconfig on anything other than a Milbeaut MV10
machine?

We've been booting other configs in QEMU for a few years now, so I
don't see why yet another config would hurt.  Maybe there's some
hardware dependency, but I guess we'd find that out trying to boot it
in QEMU.  If it boots in QEMU, I guess not booting on metal wasn't so
bad?  Maybe this is considered an antipattern, but you can see how if
we've been getting away with it for years then that would lead to such
expectations.

quoted

(whatever it is) Or does QEMU emulate a milbeaut machine?

$ qemu-system-arm -machine help

doesn't print anything that looks like it, on initial glance.  Looks
like a socionext part:
https://www.socionext.com/en/pr/sn_pr20170105_01e.pdf

quoted

If
not, better to stick with configs that are intended to boot on the
QEMU machine emulation that you are using.

I can see in our CI that we've been building+boot testing
multi_v5_defconfig, aspeed_g5_defconfig, and multi_v7_defconfig for a
while now without specifying any machine.  Is there a preferred
machine we should be using for those?  (It looks like qemu supports
ast2500-evb and ast2600-evb; is ARM1176 and ARMv6 core? Is that what
aspeed_g5 uses? Why is virt versioned? Ahhhh!!!!)

Milbeaut's serial output is on a "socionext,milbeaut-usio-uart" UART,
and its defconfig does not include drivers for the PL011 or 8250/16550
UARTs that you typically find on other boards. So how on earth would
you expect to get any output at all if QEMU does not emulate this
exact machine?

In general, if you use QEMU/mach-virt, the only defconfigs you should
reasonably be testing are the ones that contain CONFIG_ARCH_VIRT=y.

quoted

Also, while I see the point of regression testing of -next, using it
as a base to test arbitrary series and then report failures against it
produces a lot of noise. -next is *not* a good base for development,
because you get everybody else's half baked crap as well.

Ack.

quoted

When you
test my stuff, please use a known good base so we're not off on a
goose chase every time.

Goose Chase?! gOoSe ChAsE?! *gestures broadly at...everything*
Monsieur, here at the zoo, chasing the geese is not out of our
purview.  It's preferable to cleaning up after the elephants.

:-)

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