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References: <20220721172727.14624-1-angelogioacchino.delregno@collabora.com>
In-Reply-To: <20220721172727.14624-1-angelogioacchino.delregno@collabora.com>
From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Fri, 19 Aug 2022 21:28:44 +0800
Message-ID: <CAGXv+5H+BQcT=JTD3Y1necym=6uLHD8HgWpjjpyTLSin9D1KNA@mail.gmail.com>
Subject: Re: [PATCH] drm/mediatek: dsi: Add atomic {destroy, duplicate}_state,
 reset callbacks
To:     chunkuang.hu@kernel.org
Cc:     jitao.shi@mediatek.com,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>, airlied@linux.ie,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        rex-bc.chen@mediatek.com, linux-mediatek@lists.infradead.org,
        matthias.bgg@gmail.com, linux-arm-kernel@lists.infradead.org,
        xinlei.lee@mediatek.com
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On Fri, Jul 22, 2022 at 1:27 AM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> wrote:
>
> Add callbacks for atomic_destroy_state, atomic_duplicate_state and
> atomic_reset to restore functionality of the DSI driver: this solves
> vblank timeouts when another bridge is present in the chain.
>
> Tested bridge chain: DSI <=> ANX7625 => aux-bus panel
>
> Fixes: 7f6335c6a258 ("drm/mediatek: Modify dsi funcs to atomic operations")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

This patch is now needed on top of v6.0-rc1, otherwise booting will
stall for a while waiting for display vblank, which never happens
because the DSI pipeline is not configured correctly.

ChenYu

> ---
>
> Note: The commit that has been mentioned in the Fixes tag should
>       *not* have my Reviewed-by tag, as the author changed it but
>       erroneously retained the tag that I had released for an
>       earlier version of that commit (which was fine, but the new
>       version broke mtk_dsi!).
>
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 9cc406e1eee1..5b624e0f5b0a 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -808,10 +808,13 @@ static void mtk_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
>
>  static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
>         .attach = mtk_dsi_bridge_attach,
> +       .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>         .atomic_disable = mtk_dsi_bridge_atomic_disable,
> +       .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>         .atomic_enable = mtk_dsi_bridge_atomic_enable,
>         .atomic_pre_enable = mtk_dsi_bridge_atomic_pre_enable,
>         .atomic_post_disable = mtk_dsi_bridge_atomic_post_disable,
> +       .atomic_reset = drm_atomic_helper_bridge_reset,
>         .mode_set = mtk_dsi_bridge_mode_set,
>  };
>
> --
> 2.35.1
>