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Date: Thu, 2 Feb 2017 22:29:25 +0000
From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Steve Longerbeam <slongerbeam@gmail.com>
Cc: mark.rutland@arm.com, andrew-ct.chen@mediatek.com,
        minghsiu.tsai@mediatek.com, nick@shmanahar.org,
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Subject: Re: [PATCH v3 00/24] i.MX Media Driver
Message-ID: <20170202222925.GW27312@n2100.armlinux.org.uk>
References: <1483755102-24785-1-git-send-email-steve_longerbeam@mentor.com>
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On Thu, Feb 02, 2017 at 11:12:41AM -0800, Steve Longerbeam wrote:
> Here is the current .queue_setup() op in imx-media-capture.c:
> 
> static int capture_queue_setup(struct vb2_queue *vq,
>                                unsigned int *nbuffers,
>                                unsigned int *nplanes,
>                                unsigned int sizes[],
>                                struct device *alloc_devs[])
> {
>         struct capture_priv *priv = vb2_get_drv_priv(vq);
>         struct v4l2_pix_format *pix = &priv->vdev.fmt.fmt.pix;
>         unsigned int count = *nbuffers;
> 
>         if (vq->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>                 return -EINVAL;
> 
>         if (*nplanes) {
>                 if (*nplanes != 1 || sizes[0] < pix->sizeimage)
>                         return -EINVAL;
>                 count += vq->num_buffers;
>         }
> 
>         while (pix->sizeimage * count > VID_MEM_LIMIT)
>                 count--;

That's a weird way of writing:

	unsigned int max_num = VID_MEM_LIMIT / pix->sizeimage;
	count = max(count, max_num);

-- 
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