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From:   Nicolas Boichat <drinkcat@chromium.org>
Date:   Tue, 18 Aug 2020 16:19:29 +0800
Message-ID: <CANMq1KAe5o8oxzTyVMNsoZXBuopVFQqFdKassu67Fssx0xk8Ww@mail.gmail.com>
Subject: Re: [RESEND PATCH] media: camss: vfe: Use trace_printk for debugging only
To:     Andy Gross <agross@kernel.org>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Todor Tomov <todor.too@gmail.com>,
        linux-arm-msm@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>
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On Fri, Jul 10, 2020 at 2:48 PM Nicolas Boichat <drinkcat@chromium.org> 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 <drinkcat@chromium.org>
> ---
> 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
>