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

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Message-ID: <20170725155337.4ersxxu3nru7jy7q@phenom.ffwll.local>
Date:   Tue, 25 Jul 2017 17:53:37 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Xinliang Liu <z.liuxinliang@...ilicon.com>,
        Rongrong Zou <zourongrong@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Chen Feng <puck.chen@...ilicon.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Jyri Sarha <jsarha@...com>, linux-kernel@...r.kernel.org,
        Xinwei Kong <kong.kongxinwei@...ilicon.com>,
        dri-devel@...ts.freedesktop.org,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Thierry Reding <treding@...dia.com>,
        Gabriel Krisman Bertazi <krisman@...labora.co.uk>
Subject: Re: [PATCH] drm/hisilicon: fix build error without fbdev emulation

On Tue, Jul 25, 2017 at 05:33:25PM +0200, Arnd Bergmann 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)
> 
> Since the code is moved into the main probe function now, this
> adds another #ifdef.
> 
> Fixes: b4dd9f1ffaba ("drm/hisilicon: Remove custom FB helper deferred setup")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Thanks for catching this.

> ---
>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> index 1178341c3858..d48102d1a7a4 100644
> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
> @@ -121,6 +121,7 @@ static int kirin_drm_kms_init(struct drm_device *dev)
>  	/* init kms poll for handling hpd */
>  	drm_kms_helper_poll_init(dev);
>  
> +#ifdef CONFIG_DRM_FBDEV_EMULATION
>  	priv->fbdev = drm_fbdev_cma_init(dev, 32,
>  					 dev->mode_config.num_connector);
>  	if (IS_ERR(priv->fbdev)) {
> @@ -128,11 +129,13 @@ static int kirin_drm_kms_init(struct drm_device *dev)
>  		ret = PTR_ERR(priv->fbdev);
>  		goto err_cleanup_poll;
>  	}
> -
> +#endif

Could we instead stop compling out priv->fbdev? There's nothing
driver-specific here, so teh #ifdef are kinda annoying ... And saving that
one pointer in a really huge structure is somewhat silly.

>  	return 0;
>  
> +#ifdef CONFIG_DRM_FBDEV_EMULATION
>  err_cleanup_poll:
>  	drm_kms_helper_poll_fini(dev);

poll helpers aren't fbdev specific. Why do we need this? Is this just to
shut up gcc?

Thanks, Daniel

> +#endif
>  err_unbind_all:
>  	component_unbind_all(dev->dev, dev);
>  err_dc_cleanup:
> -- 
> 2.9.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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