Hi Libin
On Mon, 3 Dec 2012, Libin Yang wrote:
> Hi Guennadi,
>
> When I'm refining the patch based on your comments, I met an issue.
> Could you please help me?
>
> [snip]
>
>
> >>> -
> >>> /*
> >>> * Configure the controller for operation; caller holds the
> >>> * device mutex.
> >>> @@ -979,11 +1070,32 @@ static void mcam_vb_buf_queue(struct vb2_buffer
> >>> *vb) {
> >>> struct mcam_vb_buffer *mvb = vb_to_mvb(vb);
> >>> struct mcam_camera *cam = vb2_get_drv_priv(vb->vb2_queue);
> >>> + struct v4l2_pix_format *fmt = &cam->pix_format;
> >>> unsigned long flags;
> >>> int start;
> >>> + dma_addr_t dma_handle;
> >>> + u32 base_size = fmt->width * fmt->height;
> >>
> >>Shouldn't you be just using bytesperline? Is stride != width * height supported?
> >>
> >We will update it.
>
> [Libin] What I understand is width is the pixel number perline, so
> bytesperline = width * BytePerPixel. This means bytesperline should
> include Y data and UV data.
>
> For example, for yuv420 legacy 8-bit, it transfers like below:
> U Y Y U Y Y U Y Y U Y Y ......
> V Y Y V Y Y V Y Y V Y Y ......
>
> As each Y is one byte, so all Y data length is nuber_Y_per_line *
> height. While the nuber_Y_per_line is the pixel_per_line, which is
> fmt->width.
>
> So for the planner, the first block is saving the Y data, whose length
> is nuber_Y_per_line * height, which equals to fmt->width * height.
>
> Do I understand correctly?
>
> The base_size here means the size of Y data, so it should be fmt->width
> * fmt->height.
Right, in this case you're right. Sorry for a misleading comment. Just a
suggestion, if you prefer, you can keep the name, but maybe a name like
pixel_count or pixel_num or pixel_per_frame would be clearer for that
variable? But keeping the name is also ok with me.
> >>>
> >>> spin_lock_irqsave(&cam->dev_lock, flags);
> >>> + dma_handle = vb2_dma_contig_plane_dma_addr(vb, 0);
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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