Re: [PATCH v2] drm: renesas: rz-du: mipi_dsi: Fix return path on error

[Hugo Villeneuve <hugo@hugovil.com>]

Hi Chris,

On Wed, 22 Apr 2026 10:51:46 -0400
Chris Brandt <chris.brandt@renesas.com> wrote:

> In case of error, we should unwind correctly.
> Switching to using dmam_ instead of dma_ and moving the code earlier
> fixes the issue.
> 
> Fixes: 6f392f371650 ("drm: renesas: rz-du: Implement MIPI DSI host transfers")
> Suggested-by: Pavel Machek <pavel@nabladev.com>
> Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
> Acked-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> 
> ---
> V1->V2:
>  - Need to take into account mipi_dsi_host_register was already called (Geert)
>  - Switch to using dmam_alloc_coherent to automate unwinding (Chris)
>  - Added Acked-by (Hugo)

You should not add "Acked-by" tags if you make
modifications _after_ someone has given its Ack (unless it is just a
minor cosmetic or coding style change)...

In other words, my ack was for V1, not V2 which is quite different from
V1 :)

Don't resend a V3 just for that, I will have a look later at V2...


> ---
>  drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> index 29f2b7d24fe5..b908e702b607 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -1442,6 +1442,11 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  		return dev_err_probe(dsi->dev, PTR_ERR(dsi->prstc),
>  				     "failed to get prst\n");
> 
> +	dsi->dcs_buf_virt = dmam_alloc_coherent(dsi->dev, RZG2L_DCS_BUF_SIZE,
> +						&dsi->dcs_buf_phys, GFP_KERNEL);
> +	if (!dsi->dcs_buf_virt)
> +		return -ENOMEM;
> +
>  	platform_set_drvdata(pdev, dsi);
> 
>  	pm_runtime_enable(dsi->dev);
> @@ -1474,11 +1479,6 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		goto err_pm_disable;
> 
> -	dsi->dcs_buf_virt = dma_alloc_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE,
> -					       &dsi->dcs_buf_phys, GFP_KERNEL);
> -	if (!dsi->dcs_buf_virt)
> -		return -ENOMEM;
> -
>  	return 0;
> 
>  err_phy:
> @@ -1493,8 +1493,6 @@ static void rzg2l_mipi_dsi_remove(struct platform_device *pdev)
>  {
>  	struct rzg2l_mipi_dsi *dsi = platform_get_drvdata(pdev);
> 
> -	dma_free_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE, dsi->dcs_buf_virt,
> -			  dsi->dcs_buf_phys);
>  	mipi_dsi_host_unregister(&dsi->host);
>  	pm_runtime_disable(&pdev->dev);
>  }
> --
> 2.52.0
> 
> 


-- 
Hugo Villeneuve