Re: [PATCH v3 4/4] drm/ingenic: Fix non-OSD mode

From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Paul Cercueil <paul@crapouillou.net>
Cc: David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Sam Ravnborg <sam@ravnborg.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	od@zcrc.me, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
	stable@vger.kernel.org, Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: Re: [PATCH v3 4/4] drm/ingenic: Fix non-OSD mode
Date: Sun, 24 Jan 2021 10:30:50 +0100	[thread overview]
Message-ID: <30F302B6-04A1-472B-B026-009F7665E39C@goldelico.com> (raw)
In-Reply-To: <20210124085552.29146-5-paul@crapouillou.net>

Hi Paul,
we observed the same issue on the jz4730 (which is almost identical
to the jz4740 wrt. LCDC) and our solution [1] was simpler.

It leaves the hwdesc f0 and f1 as they are and just takes f1 for really
programming the first DMA descriptor if there is no OSD.

We have tested on jz4730 and jz4780.

Maybe you want to consider that. Then I can officially post it.

[1] https://github.com/goldelico/letux-kernel/commit/3be1de5fdabf2cc1c17f198ded3328cc6e4b9844

> Am 24.01.2021 um 09:55 schrieb Paul Cercueil <paul@crapouillou.net>:
> 
> Even though the JZ4740 did not have the OSD mode, it had (according to
> the documentation) two DMA channels, but there is absolutely no
> information about how to select the second DMA channel.
> 
> Make the ingenic-drm driver work in non-OSD mode by using the
> foreground0 plane (which is bound to the DMA0 channel) as the primary
> plane, instead of the foreground1 plane, which is the primary plane
> when in OSD mode.
> 
> Fixes: 3c9bea4ef32b ("drm/ingenic: Add support for OSD mode")
> Cc: <stable@vger.kernel.org> # v5.8+
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
> drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> index b23011c1c5d9..59ce43862e16 100644
> --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> @@ -554,7 +554,7 @@ static void ingenic_drm_plane_atomic_update(struct drm_plane *plane,
> 		height = state->src_h >> 16;
> 		cpp = state->fb->format->cpp[0];
> 
> -		if (priv->soc_info->has_osd && plane->type == DRM_PLANE_TYPE_OVERLAY)
> +		if (!priv->soc_info->has_osd || plane->type == DRM_PLANE_TYPE_OVERLAY)
> 			hwdesc = &priv->dma_hwdescs->hwdesc_f0;
> 		else
> 			hwdesc = &priv->dma_hwdescs->hwdesc_f1;

we just replace this with

                if (priv->soc_info->has_osd && plane->type != DRM_PLANE_TYPE_OVERLAY)
                        hwdesc = &priv->dma_hwdescs->hwdesc_f1;
                else
                        hwdesc = &priv->dma_hwdescs->hwdesc_f0;

and the remainder can stay as is.

> @@ -826,6 +826,7 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
> 	const struct jz_soc_info *soc_info;
> 	struct ingenic_drm *priv;
> 	struct clk *parent_clk;
> +	struct drm_plane *primary;
> 	struct drm_bridge *bridge;
> 	struct drm_panel *panel;
> 	struct drm_encoder *encoder;
> @@ -940,9 +941,11 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
> 	if (soc_info->has_osd)
> 		priv->ipu_plane = drm_plane_from_index(drm, 0);
> 
> -	drm_plane_helper_add(&priv->f1, &ingenic_drm_plane_helper_funcs);
> +	primary = priv->soc_info->has_osd ? &priv->f1 : &priv->f0;
> 
> -	ret = drm_universal_plane_init(drm, &priv->f1, 1,
> +	drm_plane_helper_add(primary, &ingenic_drm_plane_helper_funcs);
> +
> +	ret = drm_universal_plane_init(drm, primary, 1,
> 				       &ingenic_drm_primary_plane_funcs,
> 				       priv->soc_info->formats_f1,
> 				       priv->soc_info->num_formats_f1,
> @@ -954,7 +957,7 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
> 
> 	drm_crtc_helper_add(&priv->crtc, &ingenic_drm_crtc_helper_funcs);
> 
> -	ret = drm_crtc_init_with_planes(drm, &priv->crtc, &priv->f1,
> +	ret = drm_crtc_init_with_planes(drm, &priv->crtc, primary,
> 					NULL, &ingenic_drm_crtc_funcs, NULL);
> 	if (ret) {
> 		dev_err(dev, "Failed to init CRTC: %i\n", ret);
> -- 
> 2.29.2
> 

BR and thanks,
Nikolaus