[PATCH 05/20] drm/meson: Use drm_fbdev_generic_setup()

[Neil Armstrong]

Hi Noralf,

On 08/09/2018 15:46, Noralf Trønnes wrote:
> The CMA helper is already using the drm_fb_helper_generic_probe part of
> the generic fbdev emulation. This patch makes full use of the generic
> fbdev emulation by using its drm_client callbacks. This means that
> drm_mode_config_funcs->output_poll_changed and drm_driver->lastclose are
> now handled by the emulation code. Additionally fbdev unregister happens
> automatically on drm_dev_unregister().
> 
> The drm_fbdev_generic_setup() call is put after drm_dev_register() in the
> driver. This is done to highlight the fact that fbdev emulation is an
> internal client that makes use of the driver, it is not part of the
> driver as such. If fbdev setup fails, an error is printed, but the driver
> succeeds probing.


I can't really ack/nack this move, on one side it's great to have a generic fbdev emulation
instead of the old fbdev code, but on the other side the Amlogic platform (like allwinner, samsung, rockchip, ...)
still relies on an Fbdev variant of the libMali that uses smem_start...

I know it's dirty and fbdev based code should be legacy now, but I consider it like an user-space breakage...

I'll be happy if ARM provided it's Mali vendors a Fbdev libMali that could use FBINFO_HIDE_SMEM_START and allocate BO's
from the DRM driver, it won't be the case and it will never be the case until the Lima projects finalizes.

So for me it's a no-go until Lima lands upstream in Linux *and* Mesa.

Neil

> 
> Cc: Neil Armstrong <narmstrong at baylibre.com>
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> ---
>  drivers/gpu/drm/meson/meson_drv.c | 19 ++-----------------
>  drivers/gpu/drm/meson/meson_drv.h |  1 -
>  2 files changed, 2 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index d3443125e661..348b5a198b9d 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -68,15 +68,7 @@
>   * - Powering Up HDMI controller and PHY
>   */
>  
> -static void meson_fb_output_poll_changed(struct drm_device *dev)
> -{
> -	struct meson_drm *priv = dev->dev_private;
> -
> -	drm_fbdev_cma_hotplug_event(priv->fbdev);
> -}
> -
>  static const struct drm_mode_config_funcs meson_mode_config_funcs = {
> -	.output_poll_changed = meson_fb_output_poll_changed,
>  	.atomic_check        = drm_atomic_helper_check,
>  	.atomic_commit       = drm_atomic_helper_commit,
>  	.fb_create           = drm_gem_fb_create,
> @@ -282,13 +274,6 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>  
>  	drm_mode_config_reset(drm);
>  
> -	priv->fbdev = drm_fbdev_cma_init(drm, 32,
> -					 drm->mode_config.num_connector);
> -	if (IS_ERR(priv->fbdev)) {
> -		ret = PTR_ERR(priv->fbdev);
> -		goto free_drm;
> -	}
> -
>  	drm_kms_helper_poll_init(drm);
>  
>  	platform_set_drvdata(pdev, priv);
> @@ -297,6 +282,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
>  	if (ret)
>  		goto free_drm;
>  
> +	drm_fbdev_generic_setup(drm, 32);
> +
>  	return 0;
>  
>  free_drm:
> @@ -313,11 +300,9 @@ static int meson_drv_bind(struct device *dev)
>  static void meson_drv_unbind(struct device *dev)
>  {
>  	struct drm_device *drm = dev_get_drvdata(dev);
> -	struct meson_drm *priv = drm->dev_private;
>  
>  	drm_dev_unregister(drm);
>  	drm_kms_helper_poll_fini(drm);
> -	drm_fbdev_cma_fini(priv->fbdev);
>  	drm_mode_config_cleanup(drm);
>  	drm_dev_put(drm);
>  
> diff --git a/drivers/gpu/drm/meson/meson_drv.h b/drivers/gpu/drm/meson/meson_drv.h
> index 8450d6ac8c9b..aab96260da9f 100644
> --- a/drivers/gpu/drm/meson/meson_drv.h
> +++ b/drivers/gpu/drm/meson/meson_drv.h
> @@ -33,7 +33,6 @@ struct meson_drm {
>  
>  	struct drm_device *drm;
>  	struct drm_crtc *crtc;
> -	struct drm_fbdev_cma *fbdev;
>  	struct drm_plane *primary_plane;
>  
>  	/* Components Data */
>