[Intel-gfx] [PATCH v3 02/14] drm/i915/dp: return errors from rate_to_index()

[Manasi Navare]

On Wed, Mar 29, 2017 at 10:17:41AM +0300, Jani Nikula wrote:
> On Tue, 28 Mar 2017, Manasi Navare <manasi.d.navare at intel.com> wrote:
> > Won't it make more sense to squash this patch with Patch 01 in this series?
> > When i was reading Patch 1, I almost was going to comment about
> > handling the case where we dont find the index..
> 
> Matter of taste. You might then look at patch 3 and figure it should be
> squashed too... you have to draw the line somewhere, and I think it's
> always easier to review smaller pieces and be sure they are each
> correct. If you find an issue with the 2nd patch, the 1st one is still
> valid, and the follow-up review is also easier.
> 
> BR,
> Jani.
>

OK. Agreed.

Regards
Manasi 
> 
> >
> > Regards
> > Manasi
> >
> > On Tue, Mar 28, 2017 at 05:59:02PM +0300, Jani Nikula wrote:
> >> We shouldn't silently use the first element if we can't find the rate
> >> we're looking for. Make rate_to_index() more generally useful, and
> >> fallback to the first element in the caller, with a big warning.
> >> 
> >> Cc: Manasi Navare <manasi.d.navare at intel.com>
> >> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
  Reviewed-by: <manasi.d.navare at intel.com>

> >> ---
> >>  drivers/gpu/drm/i915/intel_dp.c | 13 +++++++++----
> >>  1 file changed, 9 insertions(+), 4 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >> index 88c708b07c70..0e200a37b75b 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -1544,9 +1544,9 @@ static int rate_to_index(const int *rates, int len, int rate)
> >>  
> >>  	for (i = 0; i < len; i++)
> >>  		if (rate == rates[i])
> >> -			break;
> >> +			return i;
> >>  
> >> -	return i;
> >> +	return -1;
> >>  }
> >>  
> >>  int
> >> @@ -1564,8 +1564,13 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
> >>  
> >>  int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
> >>  {
> >> -	return rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
> >> -			     rate);
> >> +	int i = rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
> >> +			      rate);
> >> +
> >> +	if (WARN_ON(i < 0))
> >> +		i = 0;
> >> +
> >> +	return i;
> >>  }
> >>  
> >>  void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
> >> -- 
> >> 2.1.4
> >> 
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center