[PATCH v3 3/9] drm/i915/dp: Move vswing/pre-emphasis adjustment calculation
Manasi Navare
manasi.d.navare at intel.com
Fri Jan 3 23:48:46 UTC 2020
On Thu, Jan 02, 2020 at 03:56:09PM +0530, Manna, Animesh wrote:
> On 02-01-2020 14:48, Jani Nikula wrote:
> >On Mon, 30 Dec 2019, Animesh Manna <animesh.manna at intel.com> wrote:
> >>vswing/pre-emphasis adjustment calculation is needed in processing
> >>of auto phy compliance request other than link training, so moved
> >>the same function in intel_dp.c.
> >I guess I'm still asking why you think this is better located in
> >intel_dp.c than intel_dp_link_training.c, as the function has been moved
> >once in the other direction already to split out stuff from intel_dp.c
> >and to make the file smaller. Even the file name suggests it should
> >really be in intel_dp_link_training.c, right?
>
> Just a thought, can we change the name to "intel_dp_link_config.c" from "intel_dp_link_training.c" which will provide little wider scope
> and all the function playing with link configuration can be under it and also exposed through header file.
>
> AFAIK, processing phy compliance request always do not need link training. I understood link training is very specific process consisting of clock recovery + channel eq.
> So I am afraid of exposing intel_get_adjust_train() from intel_dp_link_training.c which is not only specific to link-training. Need your suggestion.
>
> Regards,
> Animesh
>
I agree with Jani here and I think I had even suggested this earlier that instead of moving this function to intel_dp.c
we should make it non static so it can be used even for PHY compliance but since this function still deals
with adjusting training patterns IMHO it should still stay in intel_dp_link_training.c
Manasi
> >
> >BR,
> >Jani.
> >
> >
> >>No functional change.
> >>
> >>v1: initial patch.
> >>v2:
> >>- used "intel_dp" prefix in function name. (Jani)
> >>- used array notation instead pointer for link_status. (Ville)
> >>
> >>Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> >>---
> >> drivers/gpu/drm/i915/display/intel_dp.c | 34 ++++++++++++++++++
> >> drivers/gpu/drm/i915/display/intel_dp.h | 4 +++
> >> .../drm/i915/display/intel_dp_link_training.c | 36 ++-----------------
> >> 3 files changed, 40 insertions(+), 34 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> >>index 991f343579ef..2a27ee106089 100644
> >>--- a/drivers/gpu/drm/i915/display/intel_dp.c
> >>+++ b/drivers/gpu/drm/i915/display/intel_dp.c
> >>@@ -4110,6 +4110,40 @@ ivb_cpu_edp_signal_levels(u8 train_set)
> >> }
> >> }
> >>+void
> >>+intel_dp_get_adjust_train(struct intel_dp *intel_dp,
> >>+ const u8 link_status[DP_LINK_STATUS_SIZE])
> >>+{
> >>+ u8 v = 0;
> >>+ u8 p = 0;
> >>+ int lane;
> >>+ u8 voltage_max;
> >>+ u8 preemph_max;
> >>+
> >>+ for (lane = 0; lane < intel_dp->lane_count; lane++) {
> >>+ u8 this_v = drm_dp_get_adjust_request_voltage(link_status,
> >>+ lane);
> >>+ u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status,
> >>+ lane);
> >>+
> >>+ if (this_v > v)
> >>+ v = this_v;
> >>+ if (this_p > p)
> >>+ p = this_p;
> >>+ }
> >>+
> >>+ voltage_max = intel_dp_voltage_max(intel_dp);
> >>+ if (v >= voltage_max)
> >>+ v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
> >>+
> >>+ preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
> >>+ if (p >= preemph_max)
> >>+ p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
> >>+
> >>+ for (lane = 0; lane < 4; lane++)
> >>+ intel_dp->train_set[lane] = v | p;
> >>+}
> >>+
> >> void
> >> intel_dp_set_signal_levels(struct intel_dp *intel_dp)
> >> {
> >>diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> >>index 3da166054788..83eadc87af26 100644
> >>--- a/drivers/gpu/drm/i915/display/intel_dp.h
> >>+++ b/drivers/gpu/drm/i915/display/intel_dp.h
> >>@@ -9,6 +9,7 @@
> >> #include <linux/types.h>
> >> #include <drm/i915_drm.h>
> >>+#include <drm/drm_dp_helper.h>
> >> #include "i915_reg.h"
> >>@@ -91,6 +92,9 @@ void
> >> intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
> >> u8 dp_train_pat);
> >> void
> >>+intel_dp_get_adjust_train(struct intel_dp *intel_dp,
> >>+ const u8 link_status[DP_LINK_STATUS_SIZE]);
> >>+void
> >> intel_dp_set_signal_levels(struct intel_dp *intel_dp);
> >> void intel_dp_set_idle_link_train(struct intel_dp *intel_dp);
> >> u8
> >>diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >>index 2a1130dd1ad0..e8ff9e279800 100644
> >>--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >>+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >>@@ -34,38 +34,6 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
> >> link_status[3], link_status[4], link_status[5]);
> >> }
> >>-static void
> >>-intel_get_adjust_train(struct intel_dp *intel_dp,
> >>- const u8 link_status[DP_LINK_STATUS_SIZE])
> >>-{
> >>- u8 v = 0;
> >>- u8 p = 0;
> >>- int lane;
> >>- u8 voltage_max;
> >>- u8 preemph_max;
> >>-
> >>- for (lane = 0; lane < intel_dp->lane_count; lane++) {
> >>- u8 this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
> >>- u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
> >>-
> >>- if (this_v > v)
> >>- v = this_v;
> >>- if (this_p > p)
> >>- p = this_p;
> >>- }
> >>-
> >>- voltage_max = intel_dp_voltage_max(intel_dp);
> >>- if (v >= voltage_max)
> >>- v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
> >>-
> >>- preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
> >>- if (p >= preemph_max)
> >>- p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
> >>-
> >>- for (lane = 0; lane < 4; lane++)
> >>- intel_dp->train_set[lane] = v | p;
> >>-}
> >>-
> >> static bool
> >> intel_dp_set_link_train(struct intel_dp *intel_dp,
> >> u8 dp_train_pat)
> >>@@ -215,7 +183,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
> >> voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
> >> /* Update training set as requested by target */
> >>- intel_get_adjust_train(intel_dp, link_status);
> >>+ intel_dp_get_adjust_train(intel_dp, link_status);
> >> if (!intel_dp_update_link_train(intel_dp)) {
> >> DRM_ERROR("failed to update link training\n");
> >> return false;
> >>@@ -325,7 +293,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
> >> }
> >> /* Update training set as requested by target */
> >>- intel_get_adjust_train(intel_dp, link_status);
> >>+ intel_dp_get_adjust_train(intel_dp, link_status);
> >> if (!intel_dp_update_link_train(intel_dp)) {
> >> DRM_ERROR("failed to update link training\n");
> >> break;
More information about the dri-devel
mailing list