Re: mainline build failure due to f1e4c916f97f ("drm/edid: add EDID block count and size helpers")

[Linus Torvalds]

On Sat, May 28, 2022 at 11:59 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> It's CONFIG_ARM_AEABI, which is normally set everywhere. Without this
> option, you the kernel is built for the old 'OABI' that forces all non-packed
> struct members to be at least 16-bit aligned.

Looks like forced word (32 bit) alignment to me.

I wonder how many other structures that messes up, but I committed the
EDID fix for now.

This has presumably been broken for a long time, but maybe the
affected targets don't typically use EDID and kernel modesetting, and
only use some fixed display setup instead.

Those structure definitions go back a _loong_ time (from a quick 'git
blame' I see November 2008).

But despite that, I did not mark my fix 'cc:stable' because I don't
know if any of those machines affected by this bad arm ABI issue could
possibly care.

At least my tree hopefully now builds on them, with the BUILD_BUG_ON()
that uncovered this.

                   Linus