| Message ID | 20230418122041.1318862-4-alexander.stein@ew.tq-group.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix imx7-media-csi format settings | expand |
Hi Alexander, Thank you for the patch. The commit message should state "Lift width constraint for 16bpp formats". I would also phrase is "Relax" instead of "Lift" as it's not completely lifted. On Tue, Apr 18, 2023 at 02:20:40PM +0200, Alexander Stein wrote: > For 8-bit formats the image_width just needs to be a multiple of 8 pixels > others just a multiple of 4 pixels. This is a bit terse, and I think a word or two are missing. It could be improved: The driver unconditionally aligns the image width to multiples of 8 pixels. The real alignment constraint is 8 bytes, as indicated by the CSI_IMAG_PARA.IMAGE_WIDTH documentation that calls for 8 pixel alignment for 8bpp formats and 4 pixel alignment for other formats. > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> > --- > Changes in v3: > * Fix commit message (Only 8-bit formats needs multiple of 8 pixels) > > drivers/media/platform/nxp/imx7-media-csi.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/platform/nxp/imx7-media-csi.c b/drivers/media/platform/nxp/imx7-media-csi.c > index 1315f5743b76f..730c9c57bf4bc 100644 > --- a/drivers/media/platform/nxp/imx7-media-csi.c > +++ b/drivers/media/platform/nxp/imx7-media-csi.c > @@ -1146,6 +1146,7 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format *pixfmt, > struct v4l2_rect *compose) > { > const struct imx7_csi_pixfmt *cc; > + u32 walign; > > if (compose) { > compose->width = pixfmt->width; > @@ -1162,13 +1163,19 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format *pixfmt, > cc = imx7_csi_find_pixel_format(pixfmt->pixelformat); > } > > + /* Refer to CSI_IMAG_PARA.IMAGE_WIDTH description */ > + if (cc->bpp == 8) > + walign = 8; > + else > + walign = 4; Would the following convey the purpose better ? /* * The width alignment is 8 bytes as indicated by the * CSI_IMAG_PARA.IMAGE_WIDTH documentation. Convert it to pixels. */ walign = 8 * 8 / cc->bpp; > + > /* > * Round up width for minimum burst size. > * > * TODO: Implement configurable stride support, and check what the real > * hardware alignment constraint on the width is. > */ We can now drop the second part of the sentence :-) The first line is actually not very accurate anymore. How about /* * The width alignment is 8 bytes as indicated by the * CSI_IMAG_PARA.IMAGE_WIDTH documentation. Convert it to pixels. * * TODO: Implement configurable stride support. */ walign = 8 * 8 / cc->bpp; v4l_bound_align_image(&pixfmt->width, 1, 0xffff, walign, &pixfmt->height, 1, 0xffff, 1, 0); > - v4l_bound_align_image(&pixfmt->width, 1, 0xffff, 8, > + v4l_bound_align_image(&pixfmt->width, 1, 0xffff, walign, > &pixfmt->height, 1, 0xffff, 1, 0); > > pixfmt->bytesperline = pixfmt->width * cc->bpp / 8;
Hi Laurent, thanks for the feedback. Am Dienstag, 18. April 2023, 17:59:47 CEST schrieb Laurent Pinchart: > Hi Alexander, > > Thank you for the patch. > > The commit message should state "Lift width constraint for 16bpp > formats". To be pedantic it should be called "Lift width constraint for non-8bpp formats" :) > I would also phrase is "Relax" instead of "Lift" as it's not > completely lifted. That's true, this subtle difference should be accounted for. Thanks. > On Tue, Apr 18, 2023 at 02:20:40PM +0200, Alexander Stein wrote: > > For 8-bit formats the image_width just needs to be a multiple of 8 pixels > > others just a multiple of 4 pixels. > > This is a bit terse, and I think a word or two are missing. It could be > improved: > > The driver unconditionally aligns the image width to multiples of 8 > pixels. The real alignment constraint is 8 bytes, as indicated by the > CSI_IMAG_PARA.IMAGE_WIDTH documentation that calls for 8 pixel alignment > for 8bpp formats and 4 pixel alignment for other formats. Thanks for this suggestion. This sounds much better. > > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> > > --- > > Changes in v3: > > * Fix commit message (Only 8-bit formats needs multiple of 8 pixels) > > > > drivers/media/platform/nxp/imx7-media-csi.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/platform/nxp/imx7-media-csi.c > > b/drivers/media/platform/nxp/imx7-media-csi.c index > > 1315f5743b76f..730c9c57bf4bc 100644 > > --- a/drivers/media/platform/nxp/imx7-media-csi.c > > +++ b/drivers/media/platform/nxp/imx7-media-csi.c > > @@ -1146,6 +1146,7 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format > > *pixfmt,> > > struct v4l2_rect *compose) > > > > { > > > > const struct imx7_csi_pixfmt *cc; > > > > + u32 walign; > > > > if (compose) { > > > > compose->width = pixfmt->width; > > > > @@ -1162,13 +1163,19 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format > > *pixfmt,> > > cc = imx7_csi_find_pixel_format(pixfmt->pixelformat); > > > > } > > > > + /* Refer to CSI_IMAG_PARA.IMAGE_WIDTH description */ > > + if (cc->bpp == 8) > > + walign = 8; > > + else > > + walign = 4; > > Would the following convey the purpose better ? > > /* > * The width alignment is 8 bytes as indicated by the > * CSI_IMAG_PARA.IMAGE_WIDTH documentation. Convert it to pixels. > */ > walign = 8 * 8 / cc->bpp; I was wondering how to shorten this calculation without using ? operator, nice. > > + > > > > /* > > > > * Round up width for minimum burst size. > > * > > * TODO: Implement configurable stride support, and check what the real > > * hardware alignment constraint on the width is. > > */ > > We can now drop the second part of the sentence :-) The first line is > actually not very accurate anymore. How about > > /* > * The width alignment is 8 bytes as indicated by the > * CSI_IMAG_PARA.IMAGE_WIDTH documentation. Convert it to pixels. > * > * TODO: Implement configurable stride support. > */ > walign = 8 * 8 / cc->bpp; > v4l_bound_align_image(&pixfmt->width, 1, 0xffff, walign, > &pixfmt->height, 1, 0xffff, 1, 0); That's neat, thanks. I'll update accordingly. Best regards, Alexander > > - v4l_bound_align_image(&pixfmt->width, 1, 0xffff, 8, > > + v4l_bound_align_image(&pixfmt->width, 1, 0xffff, walign, > > > > &pixfmt->height, 1, 0xffff, 1, 0); > > > > pixfmt->bytesperline = pixfmt->width * cc->bpp / 8;
diff --git a/drivers/media/platform/nxp/imx7-media-csi.c b/drivers/media/platform/nxp/imx7-media-csi.c index 1315f5743b76f..730c9c57bf4bc 100644 --- a/drivers/media/platform/nxp/imx7-media-csi.c +++ b/drivers/media/platform/nxp/imx7-media-csi.c @@ -1146,6 +1146,7 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format *pixfmt, struct v4l2_rect *compose) { const struct imx7_csi_pixfmt *cc; + u32 walign; if (compose) { compose->width = pixfmt->width; @@ -1162,13 +1163,19 @@ __imx7_csi_video_try_fmt(struct v4l2_pix_format *pixfmt, cc = imx7_csi_find_pixel_format(pixfmt->pixelformat); } + /* Refer to CSI_IMAG_PARA.IMAGE_WIDTH description */ + if (cc->bpp == 8) + walign = 8; + else + walign = 4; + /* * Round up width for minimum burst size. * * TODO: Implement configurable stride support, and check what the real * hardware alignment constraint on the width is. */ - v4l_bound_align_image(&pixfmt->width, 1, 0xffff, 8, + v4l_bound_align_image(&pixfmt->width, 1, 0xffff, walign, &pixfmt->height, 1, 0xffff, 1, 0); pixfmt->bytesperline = pixfmt->width * cc->bpp / 8;
For 8-bit formats the image_width just needs to be a multiple of 8 pixels others just a multiple of 4 pixels. Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> --- Changes in v3: * Fix commit message (Only 8-bit formats needs multiple of 8 pixels) drivers/media/platform/nxp/imx7-media-csi.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)