]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
amdgpu: disable powerpc support for the newer display engine
authorLinus Torvalds <torvalds@linux-foundation.org>
Wed, 13 Jul 2022 19:36:50 +0000 (12:36 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 14 Jul 2022 17:05:46 +0000 (10:05 -0700)
commitd11219ad53dcf61ced53ca60fe0c4a8d34393e6c
treec866c6953e6bcb71bea3d1473b9bb01092efd097
parent4a57a8400075bc5287c5c877702c68aeae2a033d
amdgpu: disable powerpc support for the newer display engine

The DRM_AMD_DC_DCN display engine support (Raven, Navi, and newer) has
not been building cleanly on powerpc and causes link errors due to
mixing hard- and soft-float object files:

  powerpc64-linux-ld: drivers/gpu/drm/amd/amdgpu/../display/dc/dml/display_mode_lib.o uses hard float, drivers/gpu/drm/amd/amdgpu/../display/dc/dcn31/dcn31_resource.o uses soft float
  powerpc64-linux-ld: failed to merge target specific data of file drivers/gpu/drm/amd/amdgpu/../display/dc/dcn31/dcn31_resource.o
  [..]

and while patches are floating around, it's not exactly obvious what is
going on.

The problem bisects to commit 41b7a347bf14 ("powerpc: Book3S 64-bit
outline-only KASAN support") but that is probably more about changing
config variables than the fundamental cause.

Despite the bisection result, a more directly related commit seems to be
26f4712aedbd ("drm/amd/display: move FPU related code from dcn31 to
dml/dcn31 folder").  It's probably a combination of the two.

This has been going on since the merge window, without any final word.
So instead of blindly applying patches that may or may not be the right
thing, let's disable this for now.

As Michael Ellerman says:
 "IIUIC this code was never enabled on ppc before, so disabling it seems
  like a reasonable fix to get the build clean"

and once we have more actual feedback (and find any potential users) we
can always re-enable it with the patch that fixes the issues and
back-port as necessary.

Fixes: 41b7a347bf14 ("powerpc: Book3S 64-bit outline-only KASAN support")
Fixes: 26f4712aedbd ("drm/amd/display: move FPU related code from dcn31 to dml/dcn31 folder")
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/20220606153910.GA1773067@roeck-us.net/
Link: https://lore.kernel.org/all/20220618232737.2036722-1-linux@roeck-us.net/
Link: https://lore.kernel.org/all/20220713050724.GA2471738@roeck-us.net/
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/gpu/drm/amd/display/Kconfig