On Sat, Jun 29, 2024 at 08:56:09AM +0000, Sakari Ailus wrote: > Hi Laurent, > > Thanks for the patch. > > On Sat, Jun 29, 2024 at 12:26:03AM +0300, Laurent Pinchart wrote: > > When updating the link frequency control range in response to a format > > change, the minimum value passed to the __v4l2_ctrl_modify_range() > > function is hardcoded to 0, while there's no guarantee that the first > > link frequency in the menu is valid for the selected format. Fix it by > > getting using the index of the first bit set in the valid link > > frequencies mask. > > Is this a problem? The bitmask does tell which ones are valid, doesn't it? I noticed that the new range wasn't applied in my sensor driver when the minimum was set to 0 and the mask didn't include that bit. However, that's because I had the default value wrong, which caused __v4l2_ctrl_modify_range() to error out. I thought the same applied to the minimum, but that doesn't seem to be the case. Isn't it still clearer to set the correct minimum, given that it is already computed anyway, to be used as a default value ? > The minimum value will also be zero after control initialisation before > this function gets called. This should be also taken into account. > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > --- > > I noticed this issue in the CCS driver while working on a different > > sensor driver. I haven't tested this patch. > > --- > > drivers/media/i2c/ccs/ccs-core.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c > > index e1ae0f9fad43..5257dc4912ae 100644 > > --- a/drivers/media/i2c/ccs/ccs-core.c > > +++ b/drivers/media/i2c/ccs/ccs-core.c > > @@ -2143,6 +2143,7 @@ static int ccs_set_format_source(struct v4l2_subdev *subdev, > > *old_csi_format = sensor->csi_format; > > unsigned long *valid_link_freqs; > > u32 code = fmt->format.code; > > + unsigned int min, max; > > unsigned int i; > > int rval; > > > > @@ -2179,10 +2180,13 @@ static int ccs_set_format_source(struct v4l2_subdev *subdev, > > &sensor->valid_link_freqs[sensor->csi_format->compressed > > - sensor->compressed_min_bpp]; > > > > - __v4l2_ctrl_modify_range( > > - sensor->link_freq, 0, > > - __fls(*valid_link_freqs), ~*valid_link_freqs, > > - __ffs(*valid_link_freqs)); > > + min = __ffs(*valid_link_freqs); > > + man = __fls(*valid_link_freqs); > > + > > + ret = __v4l2_ctrl_modify_range(sensor->link_freq, min, max, > > + ~*valid_link_freqs, min); > > As this doesn't effect any actual change the applying of which could fail, > you'd have to have an issue with the argument values themselves. I wouldn't > add a check here. Although if you do, the sensor configuration should be > returned to the state before the call which would probably be worth a new > patch. The lack of a similar check caused my driver to silently keep the current range, and it took me a while to debug that. I however agree that, if the arguments are right, the check isn't needed. Maybe it can be dropped, as the arguments are correct. > > + if (ret) > > + return ret; > > > > return ccs_pll_update(sensor); > > } > > > > base-commit: afcd48134c58d6af45fb3fdb648f1260b20f2326 -- Regards, Laurent Pinchart
