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

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Message-Id: <2F0C9F5C-7849-458B-B18E-433BA7CFBD92@goldelico.com>
Date:   Sun, 24 Jan 2021 10:47:43 +0100
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        od@...c.me, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        stable@...r.kernel.org, Daniel Vetter <daniel.vetter@...ll.ch>
Subject: Re: [PATCH v3 4/4] drm/ingenic: Fix non-OSD mode

Hi Paul,

> Am 24.01.2021 um 10:43 schrieb Paul Cercueil <paul@...pouillou.net>:
> 
> Hi Nikolaus,
> 
> Le dim. 24 janv. 2021 à 10:30, H. Nikolaus Schaller <hns@...delico.com> a écrit :
>> 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.
> 
> Disagreed. With your solution, it ends up using priv->f1 plane with hwdesc_f0. That's very confusing.

It is a tradeoff between code simplicity and confusion. Indeed difficult to decide. Fortunately I don't have to :)

> 
>> We have tested on jz4730 and jz4780.
> 
> Could I get a tested-by then? :)

I'll test with our tree and test both SoC in the next days and give feedback.

BR and thanks,
Nikolaus

> 
> Cheers,
> -Paul
> 
>> 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@...pouillou.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@...r.kernel.org> # v5.8+
>>> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
>>> Acked-by: Daniel Vetter <daniel.vetter@...ll.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
> 
>