HI Kieran,
Thanks for your review!
On 2019-07-19 12:13:30 +0100, Kieran Bingham wrote:
> Hi Niklas,
>
> On 05/07/2019 05:55, Niklas Söderlund wrote:
> > The hardware is capable to passing V4L2_FIELD_ALTERNATE to user-space.
> > Allow users to request this field format but still default to using the
> > hardware interlacer if alternating is not explicitly requested.
>
> I'm afraid I have found this patch quite difficult to review accurately ...
Yes this have been a confusing workaround to have in the code and it's
blocking many other things I wish to do with the driver.
>
> I think I can infer that we are removing an existing workaround where
> V4L2_FIELD_ALTERNATE was converted to V4L2_FIELD_INTERLACED_xx formats,
> and also now where we used to store 'frame' heights, we store 'field'
> heights...
Yes. But it's still the default behavior to combine V4L2_FIELD_ALTERNATE
into V4L2_FIELD_INTERLACED if the sensor reports V4L2_FIELD_ALTERNATE as
I do not wish to change the user-space behavior. This only happens if
V4L2_FIELD_ANY is requested by the user. This patch allows the user to
request V4L2_FIELD_ALTERNATE and get it.
>
> Is that somewhere close as an approximation? (Perhaps it might be good
> to detail some of that in the commit message, at least any bits that are
> accurate of course)
I will try to expand the commit message thanks for pointing it out.
>
>
> I might have to look at this again later, or let some other eyeballs
> look as I'm afraid I don't feel that I've got a good overview of it yet.
>
> I wonder if it could be split in anyway to be clearer, but it's hard to
> tell :-)
>
> Perhaps it's just me being unable to see all the changes at once.
>
>
> < Some of my discussion comments below might seem out of order, as I've
> made multiple passes through this :-D >
>
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se>
> > ---
> > drivers/media/platform/rcar-vin/rcar-dma.c | 54 +++++++++++----------
> > drivers/media/platform/rcar-vin/rcar-v4l2.c | 31 +++++-------
> > 2 files changed, 42 insertions(+), 43 deletions(-)
> >
> > diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c
> > b/drivers/media/platform/rcar-vin/rcar-dma.c
> > index 372d6b106b9970d2..7ac1733455221fe0 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-dma.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-dma.c
> > @@ -526,12 +526,17 @@ static void rvin_set_coeff(struct rvin_dev *vin,
> > unsigned short xs)
> >
> > static void rvin_crop_scale_comp_gen2(struct rvin_dev *vin)
> > {
> > + unsigned int crop_height;
> > u32 xs, ys;
> >
> > /* Set scaling coefficient */
> > + crop_height = vin->crop.height;
> > + if (V4L2_FIELD_IS_INTERLACED(vin->format.field))
> > + crop_height *= 2;
> > +
> > ys = 0;
> > - if (vin->crop.height != vin->compose.height)
> > - ys = (4096 * vin->crop.height) / vin->compose.height;
> > + if (crop_height != vin->compose.height)
> > + ys = (4096 * crop_height) / vin->compose.height;
> > rvin_write(vin, ys, VNYS_REG);
> >
> > xs = 0;
> > @@ -554,16 +559,11 @@ static void rvin_crop_scale_comp_gen2(struct rvin_dev
> > *vin)
> > rvin_write(vin, 0, VNSPPOC_REG);
> > rvin_write(vin, 0, VNSLPOC_REG);
> > rvin_write(vin, vin->format.width - 1, VNEPPOC_REG);
> > - switch (vin->format.field) {
> > - case V4L2_FIELD_INTERLACED:
> > - case V4L2_FIELD_INTERLACED_TB:
> > - case V4L2_FIELD_INTERLACED_BT:
> > +
> > + if (V4L2_FIELD_IS_INTERLACED(vin->format.field))
>
> Ok, so I had to go check - V4L2_FIELD_IS_INTERLACED() does not include
> '_ALTERNATE' - so this hunk is an improvement, but a somewhat unrelated
> change.
>
> Perhaps this could be split out to before this patch, anything to
> simplify this patch would be good.
Good point, will do so for next version.
>
> > rvin_write(vin, vin->format.height / 2 - 1, VNELPOC_REG);
> > - break;
> > - default:
> > + else
> > rvin_write(vin, vin->format.height - 1, VNELPOC_REG);
> > - break;
> > - }
> >
> > vin_dbg(vin,
> > "Pre-Clip: %ux%u@%u:%u YS: %d XS: %d Post-Clip: %ux%u@%u:%u\n",
> > @@ -577,21 +577,9 @@ void rvin_crop_scale_comp(struct rvin_dev *vin)
> > /* Set Start/End Pixel/Line Pre-Clip */
> > rvin_write(vin, vin->crop.left, VNSPPRC_REG);
> > rvin_write(vin, vin->crop.left + vin->crop.width - 1, VNEPPRC_REG);
> > + rvin_write(vin, vin->crop.top, VNSLPRC_REG);
> > + rvin_write(vin, vin->crop.top + vin->crop.height - 1, VNELPRC_REG);
>
> Should those be s/vin->crop.height/crop_height/ ? <edit - no>
>
> How come there's no comparable if (V4L2_FIELD_IS_INTERLACED... in this
> function?
>
> Oh - because actually rvin_crop_scale_comp_gen2() is called from within
> this function. They are not parallel functions for two implementations.
It's awesome when someone answer there own questions ;-)
>
>
> >
> > - switch (vin->format.field) {
> > - case V4L2_FIELD_INTERLACED:
> > - case V4L2_FIELD_INTERLACED_TB:
> > - case V4L2_FIELD_INTERLACED_BT:
> > - rvin_write(vin, vin->crop.top / 2, VNSLPRC_REG);
> > - rvin_write(vin, (vin->crop.top + vin->crop.height) / 2 - 1,
> > - VNELPRC_REG);
> > - break;
>
> So - I think if i understand correctly - we used to store the
> frame-height in vin->crop, and now we store the field height.
Yes.
>
> Is that right ?
> (where field-height == frame-height on progressive frames)
Yes.
>
>
>
> > - default:
> > - rvin_write(vin, vin->crop.top, VNSLPRC_REG);
> > - rvin_write(vin, vin->crop.top + vin->crop.height - 1,
> > - VNELPRC_REG);
> > - break;
> > - }
> >
> > /* TODO: Add support for the UDS scaler. */
> > if (vin->info->model != RCAR_GEN3)
> > @@ -636,6 +624,9 @@ static int rvin_setup(struct rvin_dev *vin)
> > vnmc = VNMC_IM_ODD_EVEN;
> > progressive = true;
> > break;
> > + case V4L2_FIELD_ALTERNATE:
> > + vnmc = VNMC_IM_ODD_EVEN;
> > + break;
> > default:
> > vnmc = VNMC_IM_ODD;
> > break;
> > @@ -788,6 +779,18 @@ static bool rvin_capture_active(struct rvin_dev *vin)
> > return rvin_read(vin, VNMS_REG) & VNMS_CA;
> > }
> >
> > +static enum v4l2_field rvin_get_active_field(struct rvin_dev *vin, u32
> > vnms)
> > +{
> > + if (vin->format.field == V4L2_FIELD_ALTERNATE) {
> > + /* If FS is set it is an Even field. */
> > + if (vnms & VNMS_FS)
> > + return V4L2_FIELD_BOTTOM;
> > + return V4L2_FIELD_TOP;
> > + }
> > +
> > + return vin->format.field;
> > +}
> > +
> > static void rvin_set_slot_addr(struct rvin_dev *vin, int slot, dma_addr_t
> > addr)
> > {
> > const struct rvin_video_format *fmt;
> > @@ -937,7 +940,7 @@ static irqreturn_t rvin_irq(int irq, void *data)
> >
> > /* Capture frame */
> > if (vin->queue_buf[slot]) {
> > - vin->queue_buf[slot]->field = vin->format.field;
> > + vin->queue_buf[slot]->field = rvin_get_active_field(vin, vnms);
> > vin->queue_buf[slot]->sequence = vin->sequence;
> > vin->queue_buf[slot]->vb2_buf.timestamp = ktime_get_ns();
> > vb2_buffer_done(&vin->queue_buf[slot]->vb2_buf,
> > @@ -1064,6 +1067,7 @@ static int rvin_mc_validate_format(struct rvin_dev
> > *vin, struct v4l2_subdev *sd,
> > case V4L2_FIELD_TOP:
> > case V4L2_FIELD_BOTTOM:
> > case V4L2_FIELD_NONE:
> > + case V4L2_FIELD_ALTERNATE:
> > break;
> > case V4L2_FIELD_INTERLACED_TB:
> > case V4L2_FIELD_INTERLACED_BT:
> > diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > index d5e860ba6d9a2409..bc96ed563e365448 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > @@ -106,15 +106,7 @@ static void rvin_format_align(struct rvin_dev *vin,
> > struct v4l2_pix_format *pix)
> > case V4L2_FIELD_INTERLACED_TB:
> > case V4L2_FIELD_INTERLACED_BT:
> > case V4L2_FIELD_INTERLACED:
> > - break;
> > case V4L2_FIELD_ALTERNATE:
> > - /*
> > - * Driver does not (yet) support outputting ALTERNATE to a
> > - * userspace. It does support outputting INTERLACED so use
> > - * the VIN hardware to combine the two fields.
> > - */
> > - pix->field = V4L2_FIELD_INTERLACED;
> > - pix->height *= 2;
>
> Ok - now I get it, this used to double the format height to work around
> the lack of _ALTERNATE implementation on the sink pad/device...
>
> So this part is removal of the existing workaround.
>
>
> > break;
> > default:
> > pix->field = RVIN_DEFAULT_FIELD;
> > @@ -153,15 +145,25 @@ static int rvin_reset_format(struct rvin_dev *vin)
> >
> > v4l2_fill_pix_format(&vin->format, &fmt.format);
>
> This call v4l2_fill_pix_format() does the following:
> "vin->format.field = fmt.format.field;"
>
> Ok - so that's obtaining the *source pad format*
>
> >
> > - rvin_format_align(vin, &vin->format);
> > -
> > vin->src_rect.top = 0;
> > vin->src_rect.left = 0;
> > vin->src_rect.width = vin->format.width;
> > vin->src_rect.height = vin->format.height;
> >
> > + /* Make use of the hardware interlacer by default. */
> > + if (vin->format.field == V4L2_FIELD_ALTERNATE) {
> > + vin->format.field = V4L2_FIELD_INTERLACED;
> > + vin->format.height *= 2;
> > + }
>
> And here we are resetting the vin->format which looks like it represents
> the VIN sink device right?
Correct.
>
> I guess we are changing alternate-fields to interlaced frames to prevent
> the driver from 'passing through' alternate formats to maintain the
> user-space experience here?
Yes, the current user-space behavior is to always combine alternate to
interlaced. With this change the user can request V4L2_FIELD_ALTERNATE
and get it but if V4L2_FIELD_ANY is asked for it still gets
V4L2_FIELD_INTERLACED (if the sensor delivers V4L2_FIELD_ALTERNATE).
>
>
> > +
> > + rvin_format_align(vin, &vin->format);
> > +
> > vin->crop = vin->src_rect;
> > - vin->compose = vin->src_rect;
> > +
> > + vin->compose.top = 0;
> > + vin->compose.left = 0;
> > + vin->compose.width = vin->format.width;
> > + vin->compose.height = vin->format.height;
> >
> > return 0;
> > }
> > @@ -205,13 +207,6 @@ static int rvin_try_format(struct rvin_dev *vin, u32
> > which,
> > crop->left = 0;
> > crop->width = pix->width;
> > crop->height = pix->height;
> > -
> > - /*
> > - * If source is ALTERNATE the driver will use the VIN hardware
> > - * to INTERLACE it. The crop height then needs to be doubled.
> > - */
> > - if (pix->field == V4L2_FIELD_ALTERNATE)
> > - crop->height *= 2;
>
> And this part is just removing of the previous workaround right?
Yes.
I don't think you are so confused about this change you got it all
correctly ;-) Thanks for your effort in reviewing this!
>
>
> > }
> >
> > if (field != V4L2_FIELD_ANY)
> >
>
--
Regards,
Niklas Söderlund
