2020-07-10 06:50:38

by Nicolas Boichat

Subject: [RESEND PATCH] media: camss: vfe: Use trace_printk for debugging only

trace_printk should not be used in production code. Since
tracing interrupts is presumably latency sensitive, pr_dbg is
not appropriate, so guard the call with a preprocessor symbol
that can be defined for debugging purpose.

Signed-off-by: Nicolas Boichat <[email protected]>
---
Sent this before as part of a series (whose 4th patch was a
change that allows to detect such trace_printk), but maybe it's
easier to get individual maintainer attention by splitting it.

drivers/media/platform/qcom/camss/camss-vfe-4-1.c | 2 ++
drivers/media/platform/qcom/camss/camss-vfe-4-7.c | 2 ++
2 files changed, 4 insertions(+)

diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
index 174a36be6f5d866..0c57171fae4f9e9 100644
--- a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
+++ b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
@@ -936,8 +936,10 @@ static irqreturn_t vfe_isr(int irq, void *dev)

vfe->ops->isr_read(vfe, &value0, &value1);

+#ifdef CAMSS_VFE_TRACE_IRQ
trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n",
value0, value1);
+#endif

if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK)
vfe->isr_ops.reset_ack(vfe);
diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
index 0dca8bf9281e774..307675925e5c779 100644
--- a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
+++ b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
@@ -1058,8 +1058,10 @@ static irqreturn_t vfe_isr(int irq, void *dev)

vfe->ops->isr_read(vfe, &value0, &value1);

+#ifdef CAMSS_VFE_TRACE_IRQ
trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n",
value0, value1);
+#endif

if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK)
vfe->isr_ops.reset_ack(vfe);
--
2.27.0.383.g050319c2ae-goog

2020-08-18 08:23:05

by Nicolas Boichat

Subject: Re: [RESEND PATCH] media: camss: vfe: Use trace_printk for debugging only

On Fri, Jul 10, 2020 at 2:48 PM Nicolas Boichat <[email protected]> wrote:
>
> trace_printk should not be used in production code. Since
> tracing interrupts is presumably latency sensitive, pr_dbg is
> not appropriate, so guard the call with a preprocessor symbol
> that can be defined for debugging purpose.
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> ---
> Sent this before as part of a series (whose 4th patch was a
> change that allows to detect such trace_printk), but maybe it's
> easier to get individual maintainer attention by splitting it.

Mauro, can I get your attention on this patch? This still applies on
the latest 5.9-rc1/linux-next.

Thanks!


>
> drivers/media/platform/qcom/camss/camss-vfe-4-1.c | 2 ++
> drivers/media/platform/qcom/camss/camss-vfe-4-7.c | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
> index 174a36be6f5d866..0c57171fae4f9e9 100644
> --- a/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
> +++ b/drivers/media/platform/qcom/camss/camss-vfe-4-1.c
> @@ -936,8 +936,10 @@ static irqreturn_t vfe_isr(int irq, void *dev)
>
> vfe->ops->isr_read(vfe, &value0, &value1);
>
> +#ifdef CAMSS_VFE_TRACE_IRQ
> trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n",
> value0, value1);
> +#endif
>
> if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK)
> vfe->isr_ops.reset_ack(vfe);
> diff --git a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
> index 0dca8bf9281e774..307675925e5c779 100644
> --- a/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
> +++ b/drivers/media/platform/qcom/camss/camss-vfe-4-7.c
> @@ -1058,8 +1058,10 @@ static irqreturn_t vfe_isr(int irq, void *dev)
>
> vfe->ops->isr_read(vfe, &value0, &value1);
>
> +#ifdef CAMSS_VFE_TRACE_IRQ
> trace_printk("VFE: status0 = 0x%08x, status1 = 0x%08x\n",
> value0, value1);
> +#endif
>
> if (value0 & VFE_0_IRQ_STATUS_0_RESET_ACK)
> vfe->isr_ops.reset_ack(vfe);
> --
> 2.27.0.383.g050319c2ae-goog
>