[PATCH v2] drm/amd/display: add an ASSERT() to irq service functions

[PATCH v2] drm/amd/display: add an ASSERT() to irq service functions

[Hamza Mahfooz]

Currently, if we encounter unimplemented functions, it is difficult to
tell what caused them just by looking at dmesg and that is compounded by
the fact that it is often hard to reproduce said issues, for instance we
have had reports of this condition being triggered when removing a
secondary display that is setup in mirror mode and is connected using
usb-c. So, to have access to more detailed debugging information, add an
ASSERT() to dal_irq_service_ack() and dal_irq_service_set() that only
triggers when we encounter an unimplemented function.

Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
---
v2: detail specific instance that I'm interested in and use ASSERT()
    instead of WARN().
---
 .../gpu/drm/amd/display/dc/irq/irq_service.c    | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
index 7bad39bba86b..3d6ab4fd25cb 100644
--- a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
+++ b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
@@ -112,8 +112,15 @@ bool dal_irq_service_set(
 
 	dal_irq_service_ack(irq_service, source);
 
-	if (info->funcs && info->funcs->set)
+	if (info->funcs && info->funcs->set) {
+		if (info->funcs->set == dal_irq_service_dummy_set)
+			DC_LOG_WARNING("%s: src: %d, st: %d\n", __func__,
+				       source, enable);
+
+		ASSERT(info->funcs->set != dal_irq_service_dummy_set);
+
 		return info->funcs->set(irq_service, info, enable);
+	}
 
 	dal_irq_service_set_generic(irq_service, info, enable);
 
@@ -146,8 +153,14 @@ bool dal_irq_service_ack(
 		return false;
 	}
 
-	if (info->funcs && info->funcs->ack)
+	if (info->funcs && info->funcs->ack) {
+		if (info->funcs->ack == dal_irq_service_dummy_ack)
+			DC_LOG_WARNING("%s: src: %d\n", __func__, source);
+
+		ASSERT(info->funcs->ack != dal_irq_service_dummy_ack);
+
 		return info->funcs->ack(irq_service, info);
+	}
 
 	dal_irq_service_ack_generic(irq_service, info);
 
-- 
2.38.0

Re: [PATCH v2] drm/amd/display: add an ASSERT() to irq service functions

[Harry Wentland]

On 2022-10-17 11:38, Hamza Mahfooz wrote:
> Currently, if we encounter unimplemented functions, it is difficult to
> tell what caused them just by looking at dmesg and that is compounded by
> the fact that it is often hard to reproduce said issues, for instance we
> have had reports of this condition being triggered when removing a
> secondary display that is setup in mirror mode and is connected using
> usb-c. So, to have access to more detailed debugging information, add an
> ASSERT() to dal_irq_service_ack() and dal_irq_service_set() that only
> triggers when we encounter an unimplemented function.
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> ---
> v2: detail specific instance that I'm interested in and use ASSERT()
>     instead of WARN().
> ---
>  .../gpu/drm/amd/display/dc/irq/irq_service.c    | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> index 7bad39bba86b..3d6ab4fd25cb 100644
> --- a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> +++ b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> @@ -112,8 +112,15 @@ bool dal_irq_service_set(
>  
>  	dal_irq_service_ack(irq_service, source);
>  
> -	if (info->funcs && info->funcs->set)
> +	if (info->funcs && info->funcs->set) {
> +		if (info->funcs->set == dal_irq_service_dummy_set)
> +			DC_LOG_WARNING("%s: src: %d, st: %d\n", __func__,
> +				       source, enable);
> +
> +		ASSERT(info->funcs->set != dal_irq_service_dummy_set);

I think you'll want the ASSERT inside the if block.

Harry

> +
>  		return info->funcs->set(irq_service, info, enable);
> +	}
>  
>  	dal_irq_service_set_generic(irq_service, info, enable);
>  
> @@ -146,8 +153,14 @@ bool dal_irq_service_ack(
>  		return false;
>  	}
>  
> -	if (info->funcs && info->funcs->ack)
> +	if (info->funcs && info->funcs->ack) {
> +		if (info->funcs->ack == dal_irq_service_dummy_ack)
> +			DC_LOG_WARNING("%s: src: %d\n", __func__, source);
> +
> +		ASSERT(info->funcs->ack != dal_irq_service_dummy_ack);
> +
>  		return info->funcs->ack(irq_service, info);
> +	}
>  
>  	dal_irq_service_ack_generic(irq_service, info);
>