linux-kernel - [PATCH] drm/amd/display: Enable building new display engine with KCOV enabled

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Date:   Tue, 12 Jul 2022 15:42:47 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Harry Wentland <harry.wentland@....com>
Cc:     Alex Deucher <alexander.deucher@....com>,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Arnd Bergmann <arnd@...db.de>, Leo Li <sunpeng.li@....com>
Subject: [PATCH] drm/amd/display: Enable building new display engine with KCOV enabled

The new display engine uses floating point math, which is not supported
by KCOV. Commit 9d1d02ff3678 ("drm/amd/display: Don't build DCN1 when kcov
is enabled") tried to work around the problem by disabling
CONFIG_DRM_AMD_DC_DCN if KCOV_INSTRUMENT_ALL and KCOV_ENABLE_COMPARISONS
are enabled. The result is that KCOV can not be enabled on systems which
require this display engine. A much simpler and less invasive solution is
to disable KCOV selectively when compiling the display enagine while
keeping it enabled for the rest of the kernel.

Fixes: 9d1d02ff3678 ("drm/amd/display: Don't build DCN1 when kcov is enabled")
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Leo Li <sunpeng.li@....com>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/gpu/drm/amd/display/Kconfig     | 2 +-
 drivers/gpu/drm/amd/display/dc/Makefile | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig
index b4029c0d5d8c..96cbc87f7b6b 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 || PPC64)
 	help
 	  Choose this option if you want to use the new display engine
 	  support for AMDGPU. This adds required support for Vega and
diff --git a/drivers/gpu/drm/amd/display/dc/Makefile b/drivers/gpu/drm/amd/display/dc/Makefile
index b4eca0236435..b801973749d2 100644
--- a/drivers/gpu/drm/amd/display/dc/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/Makefile
@@ -26,6 +26,9 @@
 DC_LIBS = basics bios dml clk_mgr dce gpio irq link virtual
 
 ifdef CONFIG_DRM_AMD_DC_DCN
+
+KCOV_INSTRUMENT := n
+
 DC_LIBS += dcn20
 DC_LIBS += dsc
 DC_LIBS += dcn10
-- 
2.35.1