linux-kernel - Re: [PATCH] drm/stm: ltdc: remove call of pm-runtime functions

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Message-ID: <3b6e02b8-0f54-4eb0-9728-b304a1aa85d5@st.com>
Date:   Thu, 2 Jul 2020 12:18:46 +0000
From:   Philippe CORNU <philippe.cornu@...com>
To:     Yannick FERTRE <yannick.fertre@...com>,
        Benjamin GAIGNARD <benjamin.gaignard@...com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        "Alexandre TORGUE" <alexandre.torgue@...com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/stm: ltdc: remove call of pm-runtime functions



On 7/1/20 2:04 PM, Yannick Fertre wrote:
> It is not necessary to suspend or stop the ltdc clocks
> to modify the pixel clock.
> 
> Signed-off-by: Yannick Fertre <yannick.fertre@...com>
> ---
>   drivers/gpu/drm/stm/ltdc.c | 16 ----------------
>   1 file changed, 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 3f590d916e91..6e28f707092f 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -506,15 +506,7 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
>   				 struct drm_display_mode *adjusted_mode)
>   {
>   	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> -	struct drm_device *ddev = crtc->dev;
>   	int rate = mode->clock * 1000;
> -	bool runtime_active;
> -	int ret;
> -
> -	runtime_active = pm_runtime_active(ddev->dev);
> -
> -	if (runtime_active)
> -		pm_runtime_put_sync(ddev->dev);
>   
>   	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
>   		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> @@ -523,14 +515,6 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
>   
>   	adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
>   
> -	if (runtime_active) {
> -		ret = pm_runtime_get_sync(ddev->dev);
> -		if (ret) {
> -			DRM_ERROR("Failed to fixup mode, cannot get sync\n");
> -			return false;
> -		}
> -	}
> -
>   	DRM_DEBUG_DRIVER("requested clock %dkHz, adjusted clock %dkHz\n",
>   			 mode->clock, adjusted_mode->clock);
>   
> 
Hi Yannick,
Many thanks for your patch,
Acked-by: Philippe Cornu <philippe.cornu@...com>
Philippe :-)