Re: FAILED: patch "[PATCH] drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE" failed to apply to 4.16-stable tree

["gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>]

On Tue, Apr 24, 2018 at 08:48:42PM +0000, Deucher, Alexander wrote:
> > -----Original Message-----
> > From: Ben Crocker [mailto:bcrocker@redhat.com]
> > Sent: Tuesday, April 24, 2018 3:30 PM
> > To: gregkh@linuxfoundation.org
> > Cc: Deucher, Alexander <Alexander.Deucher@amd.com>;
> > stable@vger.kernel.org
> > Subject: Re: FAILED: patch "[PATCH] drm/radeon: insist on 32-bit DMA for
> > Cedar on PPC64/PPC64LE" failed to apply to 4.16-stable tree
> > 
> > (Third try, after turning on Plain Text mode in Gmail; apologies if you got this
> > more than once)
> > 
> > Hi Greg,
> > 
> > Thanks for the note.  I think this is a case of the same change having been
> > checked in on different branches.  I downloaded the linux-4.16.3 tarball,
> > unpacked it, and examined radeon_device.c; the correct change is there in
> > radeon_device_init (the four lines beginning "#ifdef CONFIG_PPC64").
> > 
> > Looking at the whole git log, I see two instances of exactly the same
> > patch:
> > 
> > commit bcb0b981c5571744ac446a6c906aa05a28d21446
> > Author: Ben Crocker <bcrocker@redhat.com>
> > Date:   Thu Feb 22 17:52:19 2018 -0500
> > 
> >     drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE
> > 
> > and
> > 
> > commit 2c83029cda55a5e7665c7c6326909427d6a01350
> > Author: Ben Crocker <bcrocker@redhat.com>
> > Date:   Thu Feb 22 17:52:19 2018 -0500
> > 
> >     drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE
> > 
> > A colleague of mine here at Red Hat thinks that no further action is
> > necessary; please let me know what you think.
> 
> No further action is required.  The patch was committed to drm-next
> for the next kernel and also ended up in drm-fixes for the current one
> at the time.

And it's annoying as hell.

I already argued a lot with the i915 maintainers about this in the past,
but for them, at least they have the crazy "cherry-picked from..." tag
in there showing how they are cherry picking from a _FUTURE_ commit,
which gives me a hint as to the lunacy that is happening so I can
properly detect it when it hits the tree for the second time.

But for these patches I have no clue.

Which is why all stable DRM driver patches are at the absolute bottom of
my priority queue and I dread seeing them ever show up as I don't know
what mess is going to happen whenever I try to apply them.

If you are going to do this more often in the future, at least give me a
fighting chance to detect it is happening.  Otherwise you will get a lot
of these "FAILED" emails happening, along with me just starting to
ignore radeon stable patches, like I do for i915, until they pile up and
I have nothing else better to do that day.

What a mess...

greg k-h