On Wed, 2018-07-18 at 14:08 +0100, Lee Jones wrote:
On Wed, 18 Jul 2018, Marcel Ziswiler wrote:
On Wed, 2018-07-18 at 11:12 +0100, Daniel Thompson wrote:
On Wed, Jul 18, 2018 at 10:53:35AM +0100, Lee Jones wrote:
On Wed, 18 Jul 2018, Marcel Ziswiler wrote:
On Wed, 2018-07-18 at 09:09 +0100, Lee Jones wrote:
On Mon, 16 Jul 2018, Daniel Thompson wrote:
> Currently, if the DT does not define num-interpolated- > steps > then > num_steps is undefined and the interpolation code will > deploy > randomly. > Fix this. > > Fixes: 573fe6d1c25c ("backlight: pwm_bl: Linear > interpolation > between > brightness-levels") > Reported-by: Marcel Ziswiler <marcel.ziswiler@toradex.com > > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.or > g> > Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.c > om>
This line is confusing. Did you guys author this patch together?
Yes, I reported it and we came to a conclusion together.
It sounds like you need to have all of the tags (except this one). :)
Reported-by: for reporting the issue Suggested-by: for suggesting a resolution Acked-by: for reviewing it Tested-by: for testing it
Signed-off-by usually means you either wrote a significant amount of the diffstat or you were part of the submission path.
He did [I don't object to but wouldn't have used the extra brackets you brought up ;-) ].
Yes, I take all the blame for the extra brackets. Regardless of having a masters in CS or not I still prefer too many then too few of them (;- p).
My guess is that this line should be dropped and the RB and TB tags should remain? If it was reviewed too, perhaps an AB too?
I'm OK either way and do not need any explicit authorship to be expressed for me.
In this instance I suggest keeping Reported-by and Tested-by.
> Tested-by: Marcel Ziswiler marcel.ziswiler@toradex.com > --- > drivers/video/backlight/pwm_bl.c | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/drivers/video/backlight/pwm_bl.c > b/drivers/video/backlight/pwm_bl.c > index 9ee4c1b735b2..e3c22b79fbcd 100644 > --- a/drivers/video/backlight/pwm_bl.c > +++ b/drivers/video/backlight/pwm_bl.c > @@ -299,15 +299,14 @@ static int > pwm_backlight_parse_dt(struct > device *dev, > * interpolation between each of the > values > of > brightness levels > * and creates a new pre-computed table. > */ > - of_property_read_u32(node, "num- > interpolated- > steps", > - &num_steps); > - > - /* > - * Make sure that there is at least two > entries in > the > - * brightness-levels table, otherwise we > can't > interpolate > - * between two points. > - */ > - if (num_steps) { > + if ((of_property_read_u32(node, "num- > interpolated- > steps", > + &num_steps) == > 0) > && > num_steps) {
This is pretty ugly, and isn't it suffering from over- bracketing? My suggestion would be to break out the invocation of of_property_read_u32() from the if and test only the result.
of_property_read_u32(node, "num-interpolated-steps", &num_steps);
you mean:
ret = of_property_read_u32(node, "num-interpolated- steps", &num_steps);
if (!ret && num_steps) {I haven't checked the underling code, but is it even feasible for of_property_read_u32() to not succeed AND for num_steps to be set?
If not, the check for !ret if superfluous and you can drop it.
No, then we are back to the initial issue of num_steps potentially not being initialised. We really want both of_property_read_u32() to succeed AND num_steps to actually be set.
I also think num_steps should be pre-initialised.
Yes, I guess it definitely does not hurt.
Then it will only be set if of_property_read_u32() succeeds.
Yes, but we still need to check for both, the function not failing and num_steps to actually be non zero.
Why? You don't do anything differently if it fails.
Well, maybe we should but given this being an optional property nobody cared.