Re: [PATCH] drm/exynos: fimd: fix buffer size calculation

From: Inki Dae <inki.dae@samsung.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: linux-samsung-soc@vger.kernel.org, stable@vger.kernel.org,
	Andrzej Hajda <a.hajda@samsung.com>,
	dri-devel@lists.freedesktop.org,
	Daniel Stone <daniels@collabora.com>
Subject: Re: [PATCH] drm/exynos: fimd: fix buffer size calculation
Date: Mon, 13 Apr 2015 16:48:38 +0900	[thread overview]
Message-ID: <552B74D6.4080203@samsung.com> (raw)
In-Reply-To: <1428910167-14698-1-git-send-email-m.szyprowski@samsung.com>

On 2015년 04월 13일 16:28, Marek Szyprowski wrote:
> Commit adacb228d72b9529f8de0769cc33414c3012054d ("drm: Exynos: Respect
> framebuffer pitch for FIMD/Mixer") changed the way of buffer size
> calcularion: it replaced fb_width by fb_pitch entry. fb_pitch however
> already contains '(win_data->bpp >> 3)' factor, so it should be removed
> from final buffer size calculation formula. This patch fixes this issue,
> solving possible IOMMU page fault caused by FIMD module accessing memory
> outside of the given display buffer.

This fixup had already been posted by Daniel Stone,
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?h=exynos-drm-next

Thanks,
Inki Dae

> 
> Signed-off by: Marek Szyprowski <m.szyprowski@samsung.com>
> CC: stable@vger.kernel.org  # v4.0+
> ---
>  drivers/gpu/drm/exynos/exynos_drm_fimd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> index 0e93ed792224..f29a13e0524c 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> @@ -689,7 +689,7 @@ static void fimd_win_commit(struct exynos_drm_crtc *crtc, unsigned int win)
>  	writel(val, ctx->regs + VIDWx_BUF_START(win, 0));
>  
>  	/* buffer end address */
> -	size = plane->pitch * plane->crtc_height * (plane->bpp >> 3);
> +	size = plane->pitch * plane->crtc_height;
>  	val = (unsigned long)(dma_addr + size);
>  	writel(val, ctx->regs + VIDWx_BUF_END(win, 0));
>  
> 

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