From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FFD1C43334 for ; Fri, 22 Jul 2022 12:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234876AbiGVMcR convert rfc822-to-8bit (ORCPT ); Fri, 22 Jul 2022 08:32:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230429AbiGVMcP (ORCPT ); Fri, 22 Jul 2022 08:32:15 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E703CDF0C for ; Fri, 22 Jul 2022 05:32:13 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Lq82f5Q7Kz4xG6; Fri, 22 Jul 2022 22:32:09 +1000 (AEST) From: Michael Ellerman To: Dan =?utf-8?Q?Hor=C3=A1k?= , amd-gfx@lists.freedesktop.org, Linus Torvalds , Guenter Roeck , linux-kernel@vger.kernel.org Cc: Alex Deucher , Subject: Re: [PATCH] amdgpu: re-enable DCN for ppc64le In-Reply-To: <20220722082122.571974-1-dan@danny.cz> References: <20220722082122.571974-1-dan@danny.cz> Date: Fri, 22 Jul 2022 22:32:06 +1000 Message-ID: <87o7xhcoqh.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dan, [ Cc += linuxppc-dev ] Dan Horák writes: > Commit d11219ad53dc disabled the DCN driver for all platforms that > define PPC64 due long build issues during "make allmodconfig" using > cross-compilation. Cross-compilation defaults to the ppc64_defconfig > and thus big-endian toolchain configuration. The ppc64le platform uses a > different ABI and doesn't suffer from the build issues. Unfortunately it's a bit messier than that. The build error occurs when the compiler is built to use a 64-bit long double type. The ppc64le ABI document says that long double should be 128-bits, but there are ppc64le compilers out there that are configured to use 64-bit long double, notably the kernel.org crosstool compilers. So just testing for CPU_LITTLE_ENDIAN means we'll still get build errors on those compilers. But I think we can detect the long double size and key off that. Can you test the patch below works for you? cheers diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 7aa12e88c580..e9f8cd50af99 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -281,6 +281,9 @@ config PPC # Please keep this list sorted alphabetically. # +config PCC_LONG_DOUBLE_128 + def_bool $(success,test "$(shell,echo __LONG_DOUBLE_128__ | $(CC) -E -P -)" = 1) + config PPC_BARRIER_NOSPEC bool default y diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig index b4029c0d5d8c..ec6771e87e73 100644 --- a/drivers/gpu/drm/amd/display/Kconfig +++ b/drivers/gpu/drm/amd/display/Kconfig @@ -6,7 +6,7 @@ config DRM_AMD_DC bool "AMD DC - Enable new display engine" default y select SND_HDA_COMPONENT if SND_HDA_CORE - select DRM_AMD_DC_DCN if (X86 || PPC64) && !(KCOV_INSTRUMENT_ALL && KCOV_ENABLE_COMPARISONS) + select DRM_AMD_DC_DCN if (X86 || PPC_LONG_DOUBLE_128) && !(KCOV_INSTRUMENT_ALL && KCOV_ENABLE_COMPARISONS) help Choose this option if you want to use the new display engine support for AMDGPU. This adds required support for Vega and