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Message-ID: <dde2774e-6f0b-21d0-e9c9-4a5bd1eac4e8@linaro.org>
Date:   Mon, 31 Jul 2023 15:00:25 +0200
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From:   Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH] drm/panel: Add prepare_prev_first flag to Visionox
 VTDR6130
Content-Language: en-US
To:     Jessica Zhang <quic_jesszhan@quicinc.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     quic_abhinavk@quicinc.com, quic_parellan@quicinc.com,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20230725-visionox-vtdr-prev-first-v1-1-3bc44cec7dc6@quicinc.com>
Organization: Linaro Developer Services
In-Reply-To: <20230725-visionox-vtdr-prev-first-v1-1-3bc44cec7dc6@quicinc.com>
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Hi,

On 26/07/2023 00:56, Jessica Zhang wrote:
> Due to a recent introduction of the pre_enable_prev_first bridge flag [1],
> the panel driver will be probed before the DSI is enabled, causing the
> DCS commands to fail to send.
> 
> Ensure that DSI is enabled before panel probe by setting the
> prepare_prev_first flag for the panel.

Well this is specific to MSM DSI driver, it's not related at all to the panel.

Neil

> 
> [1] commit 4fb912e5e190 ("drm/bridge: Introduce pre_enable_prev_first to alter bridge init order")
> 
> Fixes: 2349183d32d8 ("drm/panel: add visionox vtdr6130 DSI panel driver")
> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
> ---
>   drivers/gpu/drm/panel/panel-visionox-vtdr6130.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/panel/panel-visionox-vtdr6130.c b/drivers/gpu/drm/panel/panel-visionox-vtdr6130.c
> index bb0dfd86ea67..e1363e128e7e 100644
> --- a/drivers/gpu/drm/panel/panel-visionox-vtdr6130.c
> +++ b/drivers/gpu/drm/panel/panel-visionox-vtdr6130.c
> @@ -296,6 +296,7 @@ static int visionox_vtdr6130_probe(struct mipi_dsi_device *dsi)
>   	dsi->format = MIPI_DSI_FMT_RGB888;
>   	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_NO_EOT_PACKET |
>   			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
> +	ctx->panel.prepare_prev_first = true;
>   
>   	drm_panel_init(&ctx->panel, dev, &visionox_vtdr6130_panel_funcs,
>   		       DRM_MODE_CONNECTOR_DSI);
> 
> ---
> base-commit: 28a5c036b05fc5c935cc72d76abd3589825ea9cd
> change-id: 20230717-visionox-vtdr-prev-first-e00ae02eec9f
> 
> Best regards,