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Message-ID: <376dc16d-8896-0a47-b8dd-3f919c1e50bf@foss.st.com>
Date:   Tue, 13 Jun 2023 16:41:31 +0200
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Subject: Re: [PATCH v3 4/4] drm/stm: add an option to change FB bpp
To:     Dario Binacchi <dario.binacchi@amarulasolutions.com>,
        <linux-kernel@vger.kernel.org>
CC:     <michael@amarulasolutions.com>,
        Amarula patchwork <linux-amarula@amarulasolutions.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@gmail.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>,
        Yannick Fertre <yannick.fertre@foss.st.com>,
        <dri-devel@lists.freedesktop.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-stm32@st-md-mailman.stormreply.com>
References: <20230609062050.2107143-1-dario.binacchi@amarulasolutions.com>
 <20230609062050.2107143-5-dario.binacchi@amarulasolutions.com>
Content-Language: en-US
From:   Philippe CORNU <philippe.cornu@foss.st.com>
In-Reply-To: <20230609062050.2107143-5-dario.binacchi@amarulasolutions.com>
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On 6/9/23 08:20, Dario Binacchi wrote:
> Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> added parameter allows users to size, within certain limits, the memory
> footprint required by the framebuffer.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> 
> ---
> 
> Changes in v3:
> - drop [4/6] dt-bindings: display: simple: add Rocktech RK043FN48H
>    Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next):
>    https://cgit.freedesktop.org/drm/drm-misc/commit/?id=c42a37a27c777d63961dd634a30f7c887949491a
> - drop [5/6] drm/panel: simple: add support for Rocktech RK043FN48H panel
>    Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)
>    https://cgit.freedesktop.org/drm/drm-misc/commit/?id=13cdd12a9f934158f4ec817cf048fcb4384aa9dc
> 
>   drivers/gpu/drm/stm/drv.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
> index 422220df7d8c..65be2b442a6a 100644
> --- a/drivers/gpu/drm/stm/drv.c
> +++ b/drivers/gpu/drm/stm/drv.c
> @@ -30,6 +30,11 @@
>   #define STM_MAX_FB_WIDTH	2048
>   #define STM_MAX_FB_HEIGHT	2048 /* same as width to handle orientation */
>   
> +static uint stm_bpp = 16;
> +
> +MODULE_PARM_DESC(bpp, "bits-per-pixel (default: 16)");
> +module_param_named(bpp, stm_bpp, uint, 0644);
> +
>   static const struct drm_mode_config_funcs drv_mode_config_funcs = {
>   	.fb_create = drm_gem_fb_create,
>   	.atomic_check = drm_atomic_helper_check,
> @@ -93,6 +98,7 @@ static int drv_load(struct drm_device *ddev)
>   	ddev->mode_config.min_height = 0;
>   	ddev->mode_config.max_width = STM_MAX_FB_WIDTH;
>   	ddev->mode_config.max_height = STM_MAX_FB_HEIGHT;
> +	ddev->mode_config.preferred_depth = stm_bpp;
>   	ddev->mode_config.funcs = &drv_mode_config_funcs;
>   	ddev->mode_config.normalize_zpos = true;
>   
> @@ -203,7 +209,7 @@ static int stm_drm_platform_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto err_put;
>   
> -	drm_fbdev_dma_setup(ddev, 16);
> +	drm_fbdev_dma_setup(ddev, stm_bpp);
>   
>   	return 0;
>   

Acked-by: Philippe Cornu <philippe.cornu@foss.st.com>
Many thanks,
Philippe :-)