[PATCH] drm/amdgpu: Re-enable DCN for 64-bit powerpc

[Timothy Pearson]

----- Original Message -----
> From: "Linus Torvalds" <torvalds at linux-foundation.org>
> To: "Michael Ellerman" <mpe at ellerman.id.au>
> Cc: "linuxppc-dev" <linuxppc-dev at lists.ozlabs.org>, "Alex Deucher" <alexdeucher at gmail.com>, "amd-gfx"
> <amd-gfx at lists.freedesktop.org>, linux at roeck-us.net, "linux-kernel" <linux-kernel at vger.kernel.org>, "Dan Horák"
> <dan at danny.cz>, "Timothy Pearson" <tpearson at raptorengineering.com>
> Sent: Monday, July 25, 2022 2:19:57 PM
> Subject: Re: [PATCH] drm/amdgpu: Re-enable DCN for 64-bit powerpc

> On Mon, Jul 25, 2022 at 5:39 AM Michael Ellerman <mpe at ellerman.id.au> wrote:
>>
>> Further digging shows that the build failures only occur with compilers
>> that default to 64-bit long double.
> 
> Where the heck do we have 'long double' things anywhere in the kernel?
> 
> I tried to grep for it, and failed miserably. I found some constants
> that would qualify, but they were in the v4l colorspaces-details.rst
> doc file.
> 
> Strange.

We don't, at least not that I can see.  The affected code uses standard doubles.

What I'm wondering is if the compiler is getting confused between standard and long doubles when they are both the same bit length...