Hi Sakari, Hans,
On 18-11-16 15:33, Sakari Ailus wrote:
> Hi Hans,
>
> On Fri, Nov 16, 2018 at 02:31:01PM +0100, Hans Verkuil wrote:
> > On 11/16/2018 02:26 PM, Sakari Ailus wrote:
> > > Hi Marco, Michael,
> > >
> > > On Mon, Oct 29, 2018 at 07:24:07PM +0100, Marco Felsch wrote:
> > >> From: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> > >>
> > >> This patch implements the framerate selection using the skipping and
> > >> readout power-modi features. The power-modi cut the framerate by half
> > >> and each context has an independent selection bit. The same applies to
> > >> the 2x skipping feature.
> > >>
> > >> Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> > >> Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
> > >>
> > >> ---
> > >> Changelog
> > >>
> > >> v2:
> > >> - fix updating read mode register, use mt9m111_reg_mask() to update the
> > >> relevant bits only. For this purpose add reg_mask field to
> > >> struct mt9m111_mode_info.
> > >>
> > >> drivers/media/i2c/mt9m111.c | 163 ++++++++++++++++++++++++++++++++++++
> > >> 1 file changed, 163 insertions(+)
> > >>
> > >> diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c
> >
> > <snip>
> >
> > >> +static const struct mt9m111_mode_info *
> > >> +mt9m111_find_mode(struct mt9m111 *mt9m111, unsigned int req_fps,
> > >> + unsigned int width, unsigned int height)
> > >> +{
> > >> + const struct mt9m111_mode_info *mode;
> > >> + struct v4l2_rect *sensor_rect = &mt9m111->rect;
> > >> + unsigned int gap, gap_best = (unsigned int) -1;
> > >> + int i, best_gap_idx = 1;
> > >> +
> > >> + /* find best matched fps */
> > >> + for (i = 0; i < MT9M111_NUM_MODES; i++) {
> > >> + unsigned int fps = mt9m111_mode_data[i].max_fps;
> > >> +
> > >> + gap = abs(fps - req_fps);
> > >> + if (gap < gap_best) {
> > >> + best_gap_idx = i;
> > >> + gap_best = gap;
> > >> + }
> > >
> > > Could you use v4l2_find_nearest_size() instead?
I'm try to find the best matching framerate, so I think no.
> > >
> > > Also see below...
> > >
> > >> + }
> > >> +
> > >> + /*
> > >> + * Use context a/b default timing values instead of calculate blanking
> > >> + * timing values.
> > >> + */
> > >> + mode = &mt9m111_mode_data[best_gap_idx];
> > >> + mt9m111->ctx = (best_gap_idx == MT9M111_MODE_QSXGA_30FPS) ? &context_a :
> > >> + &context_b;
> > >> +
> > >> + /*
> > >> + * Check if current settings support the fps because fps selection is
> > >> + * based on the row/col skipping mechanism which has some restriction.
> > >> + */
> > >> + if (sensor_rect->width != mode->sensor_w ||
> > >> + sensor_rect->height != mode->sensor_h ||
> > >> + width > mode->max_image_w ||
> > >> + height > mode->max_image_h) {
> > >> + /* reset sensor window size */
> > >> + mt9m111->rect.left = MT9M111_MIN_DARK_COLS;
> > >> + mt9m111->rect.top = MT9M111_MIN_DARK_ROWS;
> > >> + mt9m111->rect.width = mode->sensor_w;
> > >> + mt9m111->rect.height = mode->sensor_h;
> > >> +
> > >> + /* reset image size */
> > >> + mt9m111->width = mode->max_image_w;
> > >> + mt9m111->height = mode->max_image_h;
> > >> +
> > >> + dev_warn(mt9m111->subdev.dev,
> > >> + "Warning: update image size %dx%d[%dx%d] -> %dx%d[%dx%d]\n",
> > >> + sensor_rect->width, sensor_rect->height, width, height,
> > >> + mode->sensor_w, mode->sensor_h, mode->max_image_w,
> > >> + mode->max_image_h);
> > >
> > > I wouldn't expect requesting a particular frame rate to change the sensor
> > > format. The other way around is definitely fine though.
> > >
> > > Cc Hans.
> >
> > I agree with Sakari. Changing the framerate should never change the format.
> > When you enumerate framerates those framerates are the allowed framerates
> > for the mediabus format and the resolution. So changing the framerate should
> > never modify the format or resolution. Instead, the framerate should be
> > mapped to a framerate that is valid for the format/resolution combo.
>
> I don't think this is actually documented, at least not for the sub-device
> API. I can send a patch.
Thanks for this hint. I changed it in my v3 so the format isn't touched
anymore.
Kind regards,
Marco
> --
> Sakari Ailus
> e-mail: sakari.ailus@xxxxxx
>
