Guennadi Liakhovetski <[email protected]> writes: >> This implies that even if DMA is 8 bytes aligned, width x height should >> be a multiple of 16, not 8 as I stated in the first git comment. So that >> would align : >> - width on 4 bytes (aligning meaning the lowest multiple of 4 below or >> equal to width) >> - and height on 4 bytes (aligning meaning the lowest multiple of 4 below or >> equal to height) >> >> Do we have an agreement on that specification, so that I can amend the code >> accordingly ? > > Yep, looks good to me.
All right, this should amend patch 1/4. I'll wait for the complete review to resend the patch as a whole. Cheers -- Robert commit 4d3bd5219dd3ef27f11c7061adf10f8249d2ba26 Author: Robert Jarzmik <[email protected]> Date: Fri Mar 6 22:39:41 2009 +0100 pxa_camera: Enforce YUV422P frame sizes to be 16 multiples Due to DMA constraints, the DMA chain always transfers bytes from the QIF fifos to memory in 8 bytes units. In planar formats, that could mean 0 padding between Y and U plane (and between U and V plane), which is against YUV422P standard. Therefore, a frame size is required to be a multiple of 16 (so U plane size is a multiple of 8). It is enforced in try_fmt() and set_fmt() primitives, be aligning height then width on 4 multiples as need be, to reach a 16 multiple. Signed-off-by: Robert Jarzmik <[email protected]> --- drivers/media/video/pxa_camera.c | 19 +++++++++++++++---- 1 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/media/video/pxa_camera.c b/drivers/media/video/pxa_camera.c index 54df071..f736f6b 100644 --- a/drivers/media/video/pxa_camera.c +++ b/drivers/media/video/pxa_camera.c @@ -162,6 +162,8 @@ CICR0_PERRM | CICR0_QDM | CICR0_CDM | CICR0_SOFM | \ CICR0_EOFM | CICR0_FOM) +#define PIX_YUV422P_ALIGN 16 /* YUV422P pix size should be a multiple of 16 */ + /* * Structures */ @@ -241,11 +243,8 @@ static int pxa_videobuf_setup(struct videobuf_queue *vq, unsigned int *count, dev_dbg(&icd->dev, "count=%d, size=%d\n", *count, *size); - /* planar capture requires Y, U and V buffers to be page aligned */ if (pcdev->channels == 3) - *size = roundup(icd->width * icd->height, 8) /* Y pages */ - + roundup(icd->width * icd->height / 2, 8) /* U pages */ - + roundup(icd->width * icd->height / 2, 8); /* V pages */ + *size = icd->width * icd->height * 2; else *size = roundup(icd->width * icd->height * ((icd->current_fmt->depth + 7) >> 3), 8); @@ -1297,6 +1296,18 @@ static int pxa_camera_try_fmt(struct soc_camera_device *icd, pix->width = 2048; pix->width &= ~0x01; + /* + * YUV422P planar format requires images size to be a 16 bytes + * multiple. If not, zeros will be inserted between Y and U planes, and + * U and V planes, and YUV422P standard would be violated. + */ + if (xlate->host_fmt->fourcc == V4L2_PIX_FMT_YUV422P) { + if ((pix->width * pix->height) & PIX_YUV422P_ALIGN) + pix->height = ALIGN(pix->height, PIX_YUV422P_ALIGN / 2); + if ((pix->width * pix->height) & PIX_YUV422P_ALIGN) + pix->width = ALIGN(pix->width, PIX_YUV422P_ALIGN / 2); + } + pix->bytesperline = pix->width * DIV_ROUND_UP(xlate->host_fmt->depth, 8); pix->sizeimage = pix->height * pix->bytesperline; -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
