From c653c591789b3acfa4bf6ae45d5af4f330e50a91 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Mon, 25 Jul 2022 14:37:29 +1000 Subject: drm/amdgpu: Re-enable DCN for 64-bit powerpc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit d11219ad53dc ("amdgpu: disable powerpc support for the newer display engine") disabled the DCN driver for all of powerpc due to unresolved build failures with some compilers. Further digging shows that the build failures only occur with compilers that default to 64-bit long double. Both the ppc64 and ppc64le ABIs define long double to be 128-bits, but there are compilers in the wild that default to 64-bits. The compilers provided by the major distros (Fedora, Ubuntu) default to 128-bits and are not affected by the build failure. There is a compiler flag to force 128-bit long double, which may be the correct long term fix, but as an interim fix only allow building the DCN driver if long double is 128-bits by default. The bisection in commit d11219ad53dc must have gone off the rails at some point, the build failure occurs all the way back to the original commit that enabled DCN support on powerpc, at least with some toolchains. Depends-on: d11219ad53dc ("amdgpu: disable powerpc support for the newer display engine") Fixes: 16a9dea110a6 ("amdgpu: Enable initial DCN support on POWER") Signed-off-by: Michael Ellerman Acked-by: Alex Deucher Reviewed-by: Dan Horák Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2100 Link: https://lore.kernel.org/r/20220725123918.1903255-1-mpe@ellerman.id.au --- arch/powerpc/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 7aa12e88c580..287cc2d4a4b3 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -281,6 +281,10 @@ config PPC # Please keep this list sorted alphabetically. # +config PPC_LONG_DOUBLE_128 + depends on PPC64 + def_bool $(success,test "$(shell,echo __LONG_DOUBLE_128__ | $(CC) -E -P -)" = 1) + config PPC_BARRIER_NOSPEC bool default y -- cgit v1.2.3-58-ga151