Re: [PATCH] drm/aspeed: Balance the display clock enable on teardown

[Thomas Zimmermann <tzimmermann@suse.de>]

Am 14.09.26 um 00:30 schrieb Myeonghun Pak:
> aspeed_gfx_load() enables the display clock without checking the return
> value and never disables it on probe failure or removal. devm_clk_get()
> only releases the clock reference, leaving the enable unbalanced.
>
> Use devm_clk_get_enabled() to handle enable failures and automatically
> disable and unprepare the clock on probe failure or removal.
>
> This issue was identified during our ongoing static-analysis research
> while reviewing kernel code.
>
> Fixes: 4f2a8f5898ec ("drm: Add ASPEED GFX driver")
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> Assisted-by: OpenAI:GPT-5.6

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
> Validated with an ARM64 W=1 object build and strict checkpatch.
> No hardware runtime, clock-failure injection or unbind testing was done.
>
>   drivers/gpu/drm/aspeed/aspeed_gfx_drv.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> index d4577663a..aa36b79d0 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> @@ -189,13 +189,12 @@ static int aspeed_gfx_load(struct drm_device *drm)
>   	}
>   	reset_control_deassert(priv->rst);
>   
> -	priv->clk = devm_clk_get(drm->dev, NULL);
> +	priv->clk = devm_clk_get_enabled(drm->dev, NULL);
>   	if (IS_ERR(priv->clk)) {
>   		dev_err(&pdev->dev,
> -			"missing or invalid clk device tree entry");
> +			"failed to get and enable clock\n");
>   		return PTR_ERR(priv->clk);
>   	}
> -	clk_prepare_enable(priv->clk);
>   
>   	/* Sanitize control registers */
>   	writel(0, priv->base + CRT_CTRL1);

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)