2022-07-12 23:38:22

by Guenter Roeck

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 <[email protected]>
Cc: Leo Li <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
---
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

2022-07-13 20:31:25

by Harry Wentland

Subject: Re: [PATCH] drm/amd/display: Enable building new display engine with KCOV enabled

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 <[email protected]>
> Cc: Leo Li <[email protected]>
> Signed-off-by: Guenter Roeck <[email protected]>

Reviewed-by: Harry Wentland <[email protected]>

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

2022-07-14 16:45:25

by Alex Deucher

Subject: Re: [PATCH] drm/amd/display: Enable building new display engine with KCOV enabled

Applied. Thanks!

On Wed, Jul 13, 2022 at 4:03 PM Harry Wentland <[email protected]> wrote:
>
> 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 <[email protected]>
> > Cc: Leo Li <[email protected]>
> > Signed-off-by: Guenter Roeck <[email protected]>
>
> Reviewed-by: Harry Wentland <[email protected]>
>
> 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
>

2022-07-14 18:02:18

by Guenter Roeck

Subject: Re: [PATCH] drm/amd/display: Enable building new display engine with KCOV enabled

On 7/14/22 09:29, Alex Deucher wrote:
> Applied. Thanks!
>
> On Wed, Jul 13, 2022 at 4:03 PM Harry Wentland <[email protected]> wrote:
>>
>> 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

"enagine". Outch.

Anyway, thanks for applying.

Guenter

>>> 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 <[email protected]>
>>> Cc: Leo Li <[email protected]>
>>> Signed-off-by: Guenter Roeck <[email protected]>
>>
>> Reviewed-by: Harry Wentland <[email protected]>
>>
>> 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
>>