linux-kernel - Re: [PATCH 2/3] drm/lima: Reduce the amount of logs on deferred probe

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Date:   Thu, 20 Jun 2019 08:54:57 +0800
From:   Qiang Yu <yuq825@...il.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        lima@...ts.freedesktop.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] drm/lima: Reduce the amount of logs on deferred probe

It looks like lima_clk_init will have the same problem if devm_clk_get
returns -EPROBE_DEFER.

Regards,
Qiang

On Wed, Jun 19, 2019 at 2:55 AM Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> There is no point to print deferred probe (and its failures to get
> resources) as an error.  For example getting a regulator causes three
> unneeded error messages:
>
>     lima 13000000.gpu: failed to get regulator: -517
>     lima 13000000.gpu: regulator init fail -517
>     lima 13000000.gpu: Fatal error during GPU init
>
> Also do not print clock rates before the initialization finishes
> because they will be duplicated after deferral.  Each probe step already
> prints error so remove the final error message "Fatal error during GPU
> init".
>
> In case of multiple probe tries this would pollute the dmesg.
>
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> ---
>  drivers/gpu/drm/lima/lima_device.c | 17 ++++++-----------
>  drivers/gpu/drm/lima/lima_drv.c    |  4 +---
>  2 files changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/lima/lima_device.c b/drivers/gpu/drm/lima/lima_device.c
> index 570d0e93f9a9..bb2eaa4f370e 100644
> --- a/drivers/gpu/drm/lima/lima_device.c
> +++ b/drivers/gpu/drm/lima/lima_device.c
> @@ -80,7 +80,6 @@ const char *lima_ip_name(struct lima_ip *ip)
>  static int lima_clk_init(struct lima_device *dev)
>  {
>         int err;
> -       unsigned long bus_rate, gpu_rate;
>
>         dev->clk_bus = devm_clk_get(dev->dev, "bus");
>         if (IS_ERR(dev->clk_bus)) {
> @@ -94,12 +93,6 @@ static int lima_clk_init(struct lima_device *dev)
>                 return PTR_ERR(dev->clk_gpu);
>         }
>
> -       bus_rate = clk_get_rate(dev->clk_bus);
> -       dev_info(dev->dev, "bus rate = %lu\n", bus_rate);
> -
> -       gpu_rate = clk_get_rate(dev->clk_gpu);
> -       dev_info(dev->dev, "mod rate = %lu", gpu_rate);
> -
>         err = clk_prepare_enable(dev->clk_bus);
>         if (err)
>                 return err;
> @@ -145,7 +138,8 @@ static int lima_regulator_init(struct lima_device *dev)
>                 dev->regulator = NULL;
>                 if (ret == -ENODEV)
>                         return 0;
> -               dev_err(dev->dev, "failed to get regulator: %d\n", ret);
> +               if (ret != -EPROBE_DEFER)
> +                       dev_err(dev->dev, "failed to get regulator: %d\n", ret);
>                 return ret;
>         }
>
> @@ -297,10 +291,8 @@ int lima_device_init(struct lima_device *ldev)
>         }
>
>         err = lima_regulator_init(ldev);
> -       if (err) {
> -               dev_err(ldev->dev, "regulator init fail %d\n", err);
> +       if (err)
>                 goto err_out0;
> -       }
>
>         ldev->empty_vm = lima_vm_create(ldev);
>         if (!ldev->empty_vm) {
> @@ -343,6 +335,9 @@ int lima_device_init(struct lima_device *ldev)
>         if (err)
>                 goto err_out5;
>
> +       dev_info(ldev->dev, "bus rate = %lu\n", clk_get_rate(ldev->clk_bus));
> +       dev_info(ldev->dev, "mod rate = %lu", clk_get_rate(ldev->clk_gpu));
> +
>         return 0;
>
>  err_out5:
> diff --git a/drivers/gpu/drm/lima/lima_drv.c b/drivers/gpu/drm/lima/lima_drv.c
> index b29c26cd13b2..cebc44592e47 100644
> --- a/drivers/gpu/drm/lima/lima_drv.c
> +++ b/drivers/gpu/drm/lima/lima_drv.c
> @@ -307,10 +307,8 @@ static int lima_pdev_probe(struct platform_device *pdev)
>         ldev->ddev = ddev;
>
>         err = lima_device_init(ldev);
> -       if (err) {
> -               dev_err(&pdev->dev, "Fatal error during GPU init\n");
> +       if (err)
>                 goto err_out1;
> -       }
>
>         /*
>          * Register the DRM device with the core and the connectors with
> --
> 2.17.1
>