Re: [PATCH 1/4] media: rcar-isp: ispcore: Honour requested bytesperline on RAW input

["Barnabás Pőcze" <barnabas.pocze@ideasonboard.com>]

2026. 10. 20. 15:44 keltezéssel, Niklas Söderlund írta:
> Hi Barnabás,
> 
> Thanks for your review.
> 
> On 2026-10-20 11:36:04 +0200, Barnabás Pőcze wrote:
>> Hi
>>
>> 2026. 10. 19. 21:35 keltezéssel, Niklas Söderlund írta:
>>> From: Yuya Hamamachi <yuya.hamamachi.sx@renesas.com>
>>>
>>> The RAW input video device always overwrote the bytesperline requested
>>> by userspace with width * bpp. The input buffers are however shared with
>>> the VIN, which may use a larger line stride (for example 3296 instead of
>>> 3280 bytes for a 1640 pixel wide 10 bit image). The dmabuf exported by
>>> the ISP was then smaller than the VIN buffer size, and queueing it to
>>> the VIN failed with -EINVAL:
>>>
>>>     __prepare_dmabuf: invalid dmabuf length 4042752 for plane 0,
>>>     minimum length 4060672
>>>
>>> Use the requested bytesperline if it is larger than the minimum.
>>>
>>> Signed-off-by: Yuya Hamamachi <yuya.hamamachi.sx@renesas.com>
>>> [Niklas: Use max(min(..)) instead of if statement]
>>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>>> ---
>>>    drivers/media/platform/renesas/rcar-isp/core-io.c | 11 ++++++++++-
>>>    1 file changed, 10 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/media/platform/renesas/rcar-isp/core-io.c b/drivers/media/platform/renesas/rcar-isp/core-io.c
>>> index b60b91f43d42..badde72352c1 100644
>>> --- a/drivers/media/platform/renesas/rcar-isp/core-io.c
>>> +++ b/drivers/media/platform/renesas/rcar-isp/core-io.c
>>> @@ -5,6 +5,8 @@
>>>     * Copyright (C) 2026 Ragnatech AB
>>>     */
>>> +#include <linux/sizes.h>
>>> +
>>>    #include <media/v4l2-ctrls.h>
>>>    #include <media/v4l2-event.h>
>>>    #include <media/v4l2-ioctl.h>
>>> @@ -335,6 +337,7 @@ static void risp_io_input_try_format(struct rcar_isp_core_io *io,
>>>    				     struct v4l2_pix_format_mplane *pix)
>>>    {
>>>    	unsigned int bpp = 0;
>>> +	unsigned int bpl;
>>>    	v4l_bound_align_image(&pix->width, RISP_MIN_WIDTH, RISP_MAX_WIDTH, RISP_SIZE_ALIGNMENT,
>>>    			      &pix->height, RISP_MIN_HEIGHT, RISP_MAX_HEIGHT, RISP_SIZE_ALIGNMENT,
>>> @@ -352,11 +355,17 @@ static void risp_io_input_try_format(struct rcar_isp_core_io *io,
>>>    		bpp = risp_io_input_formats[0].bpp;
>>>    	}
>>> +	/*
>>> +	 * Honour the line stride requested by userspace, the buffers are
>>> +	 * shared with the VIN which may use a larger stride than the minimum.
>>> +	 */
>>> +	bpl = max(pix->width * bpp, min(pix->plane_fmt[0].bytesperline, SZ_64K));
>>
>>    clamp(pix->plane_fmt[0].bytesperline, pix->width * bpp, SZ_64K)
> 
> Good idea.
> 
>>
>> ?
>>
>> And does the device really accept any value between these two limits?
> 
> The stride register where this is programmed is 16 bit wide.

Right, and no additional constraints in the documentation?
(I don't think I have access to that.) In any case, I think
it should be (SZ_64K - 1) then.


> 
>>
>>
>>> +
>>>    	pix->field = V4L2_FIELD_NONE;
>>>    	pix->colorspace = V4L2_COLORSPACE_RAW;
>>>    	pix->num_planes = 1;
>>> -	pix->plane_fmt[0].bytesperline = pix->width * bpp;
>>> +	pix->plane_fmt[0].bytesperline = bpl;
>>>    	pix->plane_fmt[0].sizeimage = pix->plane_fmt[0].bytesperline * pix->height;
>>>    }
>>>
>>
>