On 2022-07-12 18:42, Guenter Roeck wrote:
> 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@xxxxxxxx>
> Cc: Leo Li <sunpeng.li@xxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Harry
> ---
> 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
