linux-kernel - Re: [PATCH v2] drm/hisilicon: fix build error without fbdev emulation

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Date:   Wed, 26 Jul 2017 07:55:57 +0200
From:   Daniel Vetter <daniel.vetter@...ll.ch>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Xinliang Liu <z.liuxinliang@...ilicon.com>,
        Rongrong Zou <zourongrong@...il.com>,
        Xinwei Kong <kong.kongxinwei@...ilicon.com>,
        Chen Feng <puck.chen@...ilicon.com>,
        David Airlie <airlied@...ux.ie>,
        Sean Paul <seanpaul@...omium.org>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Gabriel Krisman Bertazi <krisman@...labora.co.uk>,
        Jani Nikula <jani.nikula@...el.com>,
        Thierry Reding <treding@...dia.com>,
        Rob Herring <robh@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] drm/hisilicon: fix build error without fbdev emulation

On Tue, Jul 25, 2017 at 8:05 PM, Arnd Bergmann <arnd@...db.de> wrote:
> We cannot reference priv->fbdev outside of the #ifdef:
>
> drivers/net/virtio_net.c:1881:12: error: 'virtnet_restore_up' defined but not used [-Werror=unused-function]
>  static int virtnet_restore_up(struct virtio_device *vdev)
> drivers/net/virtio_net.c:1859:13: error: 'virtnet_freeze_down' defined but not used [-Werror=unused-function]
>  static void virtnet_freeze_down(struct virtio_device *vdev)
>
> As the #ifdef is a bit annoying here, this removes it entirely
> and uses an IS_ENABLED() check in it place where needed.
>
> Fixes: b4dd9f1ffaba ("drm/hisilicon: Remove custom FB helper deferred setup")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

I guess I wasn't clear enough, but you don't even need the IS_ENABLED.
The cma_fini/init functions themselves don't get no-opped out (I guess
we could fix that), but the underlying fb helper functions they call
do, so this is all perfectly fine to call unconditionally. And that's
what all other drivers do. Should I edit while applying, or do you
want to respin?

Thanks, Daniel

> ---
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 19 ++++++++-----------
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h |  2 --
>  2 files changed, 8 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> index 1178341c3858..5d2dfe92f62c 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> @@ -34,12 +34,11 @@ static int kirin_drm_kms_cleanup(struct drm_device *dev)
>  {
>         struct kirin_drm_private *priv = dev->dev_private;
>
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
> -       if (priv->fbdev) {
> +       if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) && priv->fbdev) {
>                 drm_fbdev_cma_fini(priv->fbdev);
>                 priv->fbdev = NULL;
>         }
> -#endif
> +
>         drm_kms_helper_poll_fini(dev);
>         dc_ops->cleanup(to_platform_device(dev->dev));
>         drm_mode_config_cleanup(dev);
> @@ -49,20 +48,17 @@ static int kirin_drm_kms_cleanup(struct drm_device *dev)
>         return 0;
>  }
>
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
>  static void kirin_fbdev_output_poll_changed(struct drm_device *dev)
>  {
>         struct kirin_drm_private *priv = dev->dev_private;
>
>         drm_fbdev_cma_hotplug_event(priv->fbdev);
>  }
> -#endif
>
>  static const struct drm_mode_config_funcs kirin_drm_mode_config_funcs = {
>         .fb_create = drm_fb_cma_create,
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
> -       .output_poll_changed = kirin_fbdev_output_poll_changed,
> -#endif
> +       .output_poll_changed = IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) ?
> +                              kirin_fbdev_output_poll_changed : NULL,
>         .atomic_check = drm_atomic_helper_check,
>         .atomic_commit = drm_atomic_helper_commit,
>  };
> @@ -121,14 +117,15 @@ static int kirin_drm_kms_init(struct drm_device *dev)
>         /* init kms poll for handling hpd */
>         drm_kms_helper_poll_init(dev);
>
> -       priv->fbdev = drm_fbdev_cma_init(dev, 32,
> -                                        dev->mode_config.num_connector);
> +       if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION))
> +               priv->fbdev = drm_fbdev_cma_init(dev, 32,
> +                                                dev->mode_config.num_connector);
> +
>         if (IS_ERR(priv->fbdev)) {
>                 DRM_ERROR("failed to initialize fbdev.\n");
>                 ret = PTR_ERR(priv->fbdev);
>                 goto err_cleanup_poll;
>         }
> -
>         return 0;
>
>  err_cleanup_poll:
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h
> index 7f60c64915d9..56cb62df065c 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h
> @@ -20,9 +20,7 @@ struct kirin_dc_ops {
>  };
>
>  struct kirin_drm_private {
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
>         struct drm_fbdev_cma *fbdev;
> -#endif
>  };
>
>  extern const struct kirin_dc_ops ade_dc_ops;
> --
> 2.9.0
>



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch