Re: [PATCH] drm/ssd130x: Fix possible uninitialized usage of crtc_state variable

From: Geert Uytterhoeven
Date: Tue Oct 31 2023 - 09:00:29 EST


Hi Maxime,

On Tue, Oct 31, 2023 at 12:53 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
> On Tue, Oct 31, 2023 at 12:27:05PM +0100, Javier Martinez Canillas wrote:
> > Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> writes:
> > >> >> Pushed to drm-misc (drm-misc-next). Thanks!
> > >> >
> > >> > Looks like you introduced an unintended
> > >> >
> > >> > (cherry picked from commit 9e4db199e66d427c50458f4d72734cc4f0b92948)
> > >> >
> > >> > ?
> > >>
> > >> No, that's intended. It's added by the `dim cherry-pick` command, since I
> > >> had to cherry-pick to drm-misc-next-fixes the commit that was already in
> > >> the drm-misc-next branch.
> > >>
> > >> You will find that message in many drm commits, i.e:
> > >>
> > >> $ git log --oneline --grep="(cherry picked from commit" drivers/gpu/drm/ | wc -l
> > >> 1708
> > >
> > > Ah, so that's why it's (way too) common to have merge conflicts between
> > > the fixes and non-fixes drm branches :-(

> That's also not as bad as Geert put it: merging two branches with the
> exact same commit applied won't create conflict. If the two commits
> aren't exactly the same then we can indeed create conflicts, but that
> would have been the case anyway with or without the "double-commits"

Oh it is, as soon as one branch receives more commits that make changes
to the same location. Which is fairly common, too, to the point
that I am surprised when merging a drm for-next branch does not trigger
a conflict...

Cfr. the conflict I had to resolve this morning between commit
64ffd2f1d00c6235 ("drm/amd: Disable ASPM for VI w/ all Intel systems")
already upstream, and commits e5f52a84bf0a8170 ("drm/amd: Disable ASPM
for VI w/ all Intel systems") and follow-up 2757a848cb0f1848
("drm/amd: Explicitly disable ASPM when dynamic switching disabled")
in drm/drm-next.

Note that none of 64ffd2f1d00c6235 and 2757a848cb0f1848 has a "cherry
picked from commit" line in the commit description.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds