On Mon, 20 May 2024, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> On Mon, May 20, 2024 at 01:47:34PM +0300, Jani Nikula wrote:
>> On Fri, 17 May 2024, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
>> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> >
>> > Extract a helper to check whether the source+sink combo
>> > supports DSC. That basic check is needed both during mode
>> > validation and compute config. We'll also need to add extra
>> > checks to both places, so having a single place for it is nicer.
>> >
>> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> > ---
>> > drivers/gpu/drm/i915/display/intel_dp.c | 16 ++++++++++++++--
>> > 1 file changed, 14 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> > index 1e88449fe5f2..7bf283b4df7f 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> > @@ -1220,6 +1220,19 @@ bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
>> > connector->force_bigjoiner_enable;
>> > }
>> >
>> > +static bool intel_dp_has_dsc(struct intel_connector *connector)
>>
>> Why not const?
>
> We've generally not consted these things. And then whenver add
> one const somewhere it usually ends up getting in the way later,
> not because we need mutability but simply because we want to
> call something that doesn't have the const.
>
> I suppose if we do want to start consting things more we should
> just do some kind of bigger pass over the whole codebase so that
> that there's less chance of pain later.
>
> We're also not using container_of_const() for these right now,
> so the const can vanish semi-accidentally when casting things.
>
> I suppose this thing might be low level enough that the const
> could be kept. I'll have another think about it.
It's just that this series drops a bunch of const because of this, which
feels like the opposite of what you usually do. :)
BR,
Jani.
>
>>
>> > +{
>> > + struct drm_i915_private *i915 = to_i915(connector->base.dev);
>> > +
>> > + if (!HAS_DSC(i915))
>> > + return false;
>> > +
>> > + if (!drm_dp_sink_supports_dsc(connector->dp.dsc_dpcd))
>> > + return false;
>> > +
>> > + return true;
>> > +}
>> > +
>> > static enum drm_mode_status
>> > intel_dp_mode_valid(struct drm_connector *_connector,
>> > struct drm_display_mode *mode)
>> > @@ -1274,8 +1287,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>> > mode_rate = intel_dp_link_required(target_clock,
>> > intel_dp_mode_min_output_bpp(connector, mode));
>> >
>> > - if (HAS_DSC(dev_priv) &&
>> > - drm_dp_sink_supports_dsc(connector->dp.dsc_dpcd)) {
>> > + if (intel_dp_has_dsc(connector)) {
>> > enum intel_output_format sink_format, output_format;
>> > int pipe_bpp;
>>
>> --
>> Jani Nikula, Intel
--
Jani Nikula, Intel
