On Tue, 04 Apr 2017, Hans Verkuil wrote:
> On 04/04/2017 03:01 PM, Lee Jones wrote:
> > On Tue, 04 Apr 2017, Lee Jones wrote:
> >
> >> On Tue, 04 Apr 2017, Hans Verkuil wrote:
> >>
> >>> On 04/04/2017 02:32 PM, Lee Jones wrote:
> >>>> If CONFIG_RC_CORE is not enabled then none of the RC code will be
> >>>> executed anyway, so we're placing the capability check inside the
> >>>>
> >>>> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> >>>> ---
> >>>> drivers/media/cec/cec-core.c | 2 +-
> >>>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
> >>>> index 37217e2..06a312c 100644
> >>>> --- a/drivers/media/cec/cec-core.c
> >>>> +++ b/drivers/media/cec/cec-core.c
> >>>> @@ -234,10 +234,10 @@ struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
> >>>> return ERR_PTR(res);
> >>>> }
> >>>>
> >>>> +#if IS_REACHABLE(CONFIG_RC_CORE)
> >>>> if (!(caps & CEC_CAP_RC))
> >>>> return adap;
> >>>>
> >>>> -#if IS_REACHABLE(CONFIG_RC_CORE)
> >>>> /* Prepare the RC input device */
> >>>> adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
> >>>> if (!adap->rc) {
> >>>>
> >>>
> >>> Not true, there is an #else further down.
> >>
> >> I saw the #else. It's inert code that becomes function-less.
> >>
> >>> That said, this code is clearly a bit confusing.
> >>>
> >>> It would be better if at the beginning of the function we'd have this:
> >>>
> >>> #if !IS_REACHABLE(CONFIG_RC_CORE)
> >>> caps &= ~CEC_CAP_RC;
> >>> #endif
> >>>
> >>> and then drop the #else bit and (as you do in this patch) move the #if up.
> >>>
> >>> Can you make a new patch for this?
> >>
> >> Sure.
> >
> > No wait, sorry! This patch is the correct fix.
> >
> > 'caps' is already indicating !CEC_CAP_RC, which is right.
> >
> > What we're trying to do here is only consider looking at the
> > capabilities if the RC Core is enabled. If it is not enabled, the #if
> > still does the right thing and makes sure that the caps are updated.
> >
> > Please take another look at the semantics.
>
> Ah, yes. You are right. But so am I: the code is just unnecessarily confusing
> as is seen by this discussion.
>
> I still would like to see a patch with my proposed solution. The control flow
> is much easier to understand that way.
I have an idea. Please bear with me.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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