Re: [PATCH v6 05/11] drm/mediatek: mtk_dsi: Enable interrupt at component bind time

[CK Hu (胡俊光)]

On Wed, 2026-07-15 at 15:56 +0200, AngeloGioacchino Del Regno wrote:
> Having the DSI interrupt enabled before actually binding the DSI
> component to the display controller driver is both useless and
> dangerous: the main purpose of this interrupt is to signal CMD
> done, LP RX data ready, or VideoMode done, or to reset the HW
> engine if this doesn't come.
> 
> Should this interrupt come too late (during probe), the HW will
> be reset only at the next occurrence of a timeout, which slows
> down boot and may render artifacts to the DSI display.
> 
> Moreover, clearing the DSI interrupt while the display controller
> is not ready yet, may result in an interrupt storm.
> 
> In order to prevent this from happening, request the interrupt
> with IRQF_NO_AUTOEN, and enable it only when binding DSI to its
> display controller component master.

Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>

> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index e3d7338c35e3..d1aa258e3799 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -225,6 +225,7 @@ struct mtk_dsi {
>  	int refcount;
>  	bool enabled;
>  	bool lanes_ready;
> +	int irq;
>  	u32 irq_data;
>  	wait_queue_head_t irq_wait_queue;
>  	const struct mtk_dsi_driver_data *driver_data;
> @@ -1096,6 +1097,8 @@ static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
>  		return ret;
>  	}
>  
> +	enable_irq(dsi->irq);
> +
>  	return 0;
>  }
>  
> @@ -1104,6 +1107,8 @@ static void mtk_dsi_unbind(struct device *dev, struct device *master,
>  {
>  	struct mtk_dsi *dsi = dev_get_drvdata(dev);
>  
> +	disable_irq(dsi->irq);
> +
>  	drm_encoder_cleanup(&dsi->encoder);
>  }
>  
> @@ -1337,7 +1342,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	int irq_num;
>  	int ret;
>  
>  	dsi = devm_drm_bridge_alloc(dev, struct mtk_dsi, bridge,
> @@ -1370,9 +1374,9 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  	if (IS_ERR(dsi->phy))
>  		return dev_err_probe(dev, PTR_ERR(dsi->phy), "Failed to get MIPI-DPHY\n");
>  
> -	irq_num = platform_get_irq(pdev, 0);
> -	if (irq_num < 0)
> -		return irq_num;
> +	dsi->irq = platform_get_irq(pdev, 0);
> +	if (dsi->irq < 0)
> +		return dsi->irq;
>  
>  	dsi->host.ops = &mtk_dsi_ops;
>  	dsi->host.dev = dev;
> @@ -1381,17 +1385,15 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, dsi);
>  
> +	ret = devm_request_irq(&pdev->dev, dsi->irq, mtk_dsi_irq,
> +			       IRQF_NO_AUTOEN, dev_name(&pdev->dev), dsi);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "Failed to request DSI irq\n");
> +
>  	ret = mipi_dsi_host_register(&dsi->host);
>  	if (ret < 0)
>  		return dev_err_probe(dev, ret, "Failed to register DSI host\n");
>  
> -	ret = devm_request_irq(&pdev->dev, irq_num, mtk_dsi_irq,
> -			       IRQF_TRIGGER_NONE, dev_name(&pdev->dev), dsi);
> -	if (ret) {
> -		mipi_dsi_host_unregister(&dsi->host);
> -		return dev_err_probe(&pdev->dev, ret, "Failed to request DSI irq\n");
> -	}
> -
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>