linux-kernel - Re: [PATCH] drm/rockchip: avoid 64-bit division

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Message-ID: <20241104172950.GA741087@thelio-3990X>
Date: Mon, 4 Nov 2024 10:29:50 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Arnd Bergmann <arnd@...nel.org>, Sandy Huang <hjc@...k-chips.com>,
	Heiko Stübner <heiko@...ech.de>,
	Andy Yan <andy.yan@...k-chips.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>
Cc: David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Algea Cao <algea.cao@...k-chips.com>,
	Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
	Arnd Bergmann <arnd@...db.de>, dri-devel@...ts.freedesktop.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/rockchip: avoid 64-bit division

On Fri, Oct 18, 2024 at 03:10:10PM +0000, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> Dividing a 64-bit integer prevents building this for 32-bit targets:
> 
> ERROR: modpost: "__aeabi_uldivmod" [drivers/gpu/drm/rockchip/rockchipdrm.ko] undefined!
> 
> As this function is not performance criticial, just Use the div_u64() helper.
> 
> Fixes: 128a9bf8ace2 ("drm/rockchip: Add basic RK3588 HDMI output support")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Reviewed-by: Nathan Chancellor <nathan@...nel.org>

Can someone please pick this up? It is still broken in next-20241104...

https://storage.tuxsuite.com/public/clangbuiltlinux/continuous-integration2/builds/2oNvJFRj8tkDieb6VfrMf4rh1Kn/build.log

> ---
>  drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> index 9c796ee4c303..c8b362cc2b95 100644
> --- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> @@ -82,7 +82,7 @@ static void dw_hdmi_qp_rockchip_encoder_enable(struct drm_encoder *encoder)
>  		 * comment in rk_hdptx_phy_power_on() from
>  		 * drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
>  		 */
> -		phy_set_bus_width(hdmi->phy, rate / 100);
> +		phy_set_bus_width(hdmi->phy, div_u64(rate, 100));
>  	}
>  }
>  
> -- 
> 2.39.5
>