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Message-ID: <85b8cdf7-a05f-44d2-a678-af121231261f@xs4all.nl>
Date:   Mon, 4 Dec 2023 16:10:08 +0100
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Subject: Re: [PATCH v2 33/36] media: ti: cal: Fix misuse of min_buffers_needed
 field
Content-Language: en-US, nl
To:     Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com,
        matt.ranostay@konsulko.com
Cc:     linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        linux-staging@lists.linux.dev, kernel@collabora.com,
        Benoit Parrot <bparrot@ti.com>
References: <20231204132323.22811-1-benjamin.gaignard@collabora.com>
 <20231204132323.22811-34-benjamin.gaignard@collabora.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
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In-Reply-To: <20231204132323.22811-34-benjamin.gaignard@collabora.com>
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Precedence: bulk

On 04/12/2023 14:23, Benjamin Gaignard wrote:
> 'min_buffers_needed' is suppose to be used to indicate the number
> of buffers needed by DMA engine to start streaming.
> Cal driver doesn't use DMA engine and just want to specify
> the minimum number of buffers to allocate when calling VIDIOC_REQBUFS.
> That 'min_reqbufs_allocation' field purpose so use it.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> CC: Benoit Parrot <bparrot@ti.com>
> ---
>  drivers/media/platform/ti/cal/cal-video.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/ti/cal/cal-video.c b/drivers/media/platform/ti/cal/cal-video.c
> index e1c5e68e945b..04709dac7221 100644
> --- a/drivers/media/platform/ti/cal/cal-video.c
> +++ b/drivers/media/platform/ti/cal/cal-video.c
> @@ -1010,7 +1010,7 @@ int cal_ctx_v4l2_init(struct cal_ctx *ctx)
>  	q->mem_ops = &vb2_dma_contig_memops;
>  	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
>  	q->lock = &ctx->mutex;
> -	q->min_buffers_needed = 3;
> +	q->min_reqbufs_allocation = 3;
>  	q->dev = ctx->cal->dev;
>  
>  	ret = vb2_queue_init(q);

This driver definitely needs 1 buffer before it can start DMA, so set
min_buffers_needed to 1.

Regards,

	Hans