Re: [RFC v4 09/20] drm/i915/dp: Extract drm_dp_has_mst()

Jani Nikula
2020-08-26T06:51:29Z

On Tue, 25 Aug 2020, Lyude Paul <lyude@redhat.com> wrote:
> Just a tiny drive-by cleanup, we can consolidate i915's code for
> checking for MST support into a helper to be shared across drivers.
>
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Reviewed-by: Sean Paul <sean@poorly.run>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 18 ++----------------
> include/drm/drm_dp_mst_helper.h | 22 ++++++++++++++++++++++
> 2 files changed, 24 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 79c27f91f42c0..1e29d3a012856 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4699,20 +4699,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> return true;
> }
>
> -static bool
> -intel_dp_sink_can_mst(struct intel_dp *intel_dp)
> -{
> - u8 mstm_cap;
> -
> - if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
> - return false;
> -
> - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_MSTM_CAP, &mstm_cap) != 1)
> - return false;
> -
> - return mstm_cap & DP_MST_CAP;
> -}
> -
> static bool
> intel_dp_can_mst(struct intel_dp *intel_dp)
> {
> @@ -4720,7 +4706,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
>
> return i915->params.enable_dp_mst &&
> intel_dp->can_mst &&
> - intel_dp_sink_can_mst(intel_dp);
> + drm_dp_has_mst(&intel_dp->aux, intel_dp->dpcd);
> }
>
> static void
> @@ -4729,7 +4715,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> struct intel_encoder *encoder =
> &dp_to_dig_port(intel_dp)->base;
> - bool sink_can_mst = intel_dp_sink_can_mst(intel_dp);
> + bool sink_can_mst = drm_dp_has_mst(&intel_dp->aux, intel_dp->dpcd);
>
> drm_dbg_kms(&i915->drm,
> "[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam: %s\n",
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 8b9eb4db3381c..2d8983a713e8c 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -911,4 +911,26 @@ __drm_dp_mst_state_iter_get(struct drm_atomic_state *state,
> for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
> for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), NULL, &(new_state), (__i)))
>
> +/**
> + * drm_dp_has_mst() - check whether or not a sink supports MST
> + * @aux: The DP AUX channel to use
> + * @dpcd: A cached copy of the DPCD capabilities for this sink
> + *
> + * Returns: %True if the sink supports MST, %false otherwise
> + */
> +static inline bool

I've become more and more critical of accumulating a lot of inlines in
headers. Do we really want this in the header?

> +drm_dp_has_mst(struct drm_dp_aux *aux,
> + const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> +{
> + u8 mstm_cap;
> +
> + if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
> + return false;
> +
> + if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
> + return false;
> +
> + return !!(mstm_cap & DP_MST_CAP);

The !! is superfluous.

BR,
Jani.

> +}
> +
> #endif

--
Jani Nikula, Intel Open Source Graphics Center