Re: [PATCH 2/3] drm/exynos: exynos_dp: change poweron/off to encoder enable/disable

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 27.10.2026 13:01, Alexandre Marquet via B4 Relay wrote:
> From: Alexandre Marquet <tb@a-marquet.fr>
>
> Current functions exynos_dp_poweron()/exynos_dp_poweroff(), that
> supposedly powers on/off the device, actually only enable the encoder
> clock. This cause issues where poweron() calls fail silently in
> analogix_dp_probe(), leading in some cases to a state were the encoder
> is never enabled but the rest of the driver assumes that it is.
>
> Signed-off-by: Alexandre Marquet <tb@a-marquet.fr>

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Snow, Peach-Pit and Peach-Pi Chromebooks work fine with this change.

> ---
>  drivers/gpu/drm/exynos/exynos_dp.c | 40 +++++++++++++-------------------------
>  1 file changed, 13 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_dp.c b/drivers/gpu/drm/exynos/exynos_dp.c
> index 82c238829921..16b00aacd55b 100644
> --- a/drivers/gpu/drm/exynos/exynos_dp.c
> +++ b/drivers/gpu/drm/exynos/exynos_dp.c
> @@ -43,39 +43,27 @@ struct exynos_dp_device {
>  	struct analogix_dp_plat_data plat_data;
>  };
>  
> -static int exynos_dp_crtc_clock_enable(struct analogix_dp_plat_data *plat_data,
> -				bool enable)
> -{
> -	struct exynos_dp_device *dp = to_dp(plat_data);
> -	struct drm_encoder *encoder = &dp->encoder;
> -
> -	if (!encoder->crtc)
> -		return -EPERM;
> -
> -	exynos_drm_pipe_clk_enable(to_exynos_crtc(encoder->crtc), enable);
> -
> -	return 0;
> -}
> -
> -static int exynos_dp_poweron(struct analogix_dp_plat_data *plat_data)
> +static void exynos_dp_mode_set(struct drm_encoder *encoder,
> +			       struct drm_display_mode *mode,
> +			       struct drm_display_mode *adjusted_mode)
>  {
> -	return exynos_dp_crtc_clock_enable(plat_data, true);
>  }
>  
> -static int exynos_dp_poweroff(struct analogix_dp_plat_data *plat_data)
> +static void exynos_dp_crtc_clock_enable(struct drm_encoder *encoder,
> +					bool enable)
>  {
> -	return exynos_dp_crtc_clock_enable(plat_data, false);
> +	if (encoder->crtc)
> +		exynos_drm_pipe_clk_enable(to_exynos_crtc(encoder->crtc), enable);
>  }
>  
> -static void exynos_dp_mode_set(struct drm_encoder *encoder,
> -			       struct drm_display_mode *mode,
> -			       struct drm_display_mode *adjusted_mode)
> +static void exynos_dp_enable(struct drm_encoder *encoder)
>  {
> +	exynos_dp_crtc_clock_enable(encoder, true);
>  }
>  
> -static void exynos_dp_nop(struct drm_encoder *encoder)
> +static void exynos_dp_disable(struct drm_encoder *encoder)
>  {
> -	/* do nothing */
> +	exynos_dp_crtc_clock_enable(encoder, false);
>  }
>  
>  static const struct drm_encoder_funcs exynos_dp_encoder_funcs = {
> @@ -84,8 +72,8 @@ static const struct drm_encoder_funcs exynos_dp_encoder_funcs = {
>  
>  static const struct drm_encoder_helper_funcs exynos_dp_encoder_helper_funcs = {
>  	.mode_set = exynos_dp_mode_set,
> -	.enable = exynos_dp_nop,
> -	.disable = exynos_dp_nop,
> +	.enable = exynos_dp_enable,
> +	.disable = exynos_dp_disable,
>  };
>  
>  static int exynos_dp_bind(struct device *dev, struct device *master, void *data)
> @@ -171,8 +159,6 @@ static int exynos_dp_probe(struct platform_device *pdev)
>  
>  	/* The remote port can be either a panel or a bridge */
>  	dp->plat_data.dev_type = EXYNOS_DP;
> -	dp->plat_data.power_on = exynos_dp_poweron;
> -	dp->plat_data.power_off = exynos_dp_poweroff;
>  	dp->plat_data.ops = &exynos_dp_ops;
>  
>  	dp->adp = analogix_dp_probe(dev, &dp->plat_data);
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland