On Tue, 2016-01-05 at 18:20 +0530, Shubhangi Shrivastava wrote:
> When created originally intel_dp_check_link_status()
> was supposed to handle only link training for short
> pulse but has grown into handler for short pulse itself.
> This patch cleans up this function by splitting it into
> two halves. First intel_dp_short_pulse() is called,
> which will be entry point and handle all logic for
> short pulse handling while intel_dp_check_link_status()
> will retain its original purpose of only doing link
> status related work.
> The link retraining part when EQ is not correct is
> retained to intel_dp_check_link_status whereas other
> operations are handled as part of intel_dp_short_pulse.
> This change is required to avoid performing all DPCD
> related operations on performing link retraining.
>
> Tested-by: Nathan D Ciobanu <nathan.d.ciobanu@xxxxxxxxx>
> Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx>
> Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 56 ++++++++++++++++++++++++----------------
> -
> 1 file changed, 33 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 137757b..842790e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4289,6 +4289,33 @@ go_again:
> return -EINVAL;
> }
>
> +static void
> +intel_dp_check_link_status(struct intel_dp *intel_dp)
> +{
> + struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)
> ->base;
> + u8 link_status[DP_LINK_STATUS_SIZE];
> +
> + if (!intel_dp_get_link_status(intel_dp, link_status)) {
> + DRM_ERROR("Failed to get link status\n");
> + return;
> + }
> +
> + if (!intel_encoder->base.crtc)
> + return;
> +
> + if (!to_intel_crtc(intel_encoder->base.crtc)->active)
> + return;
> +
> + /* if link training is requested we should perform it always */
> + if ((intel_dp->compliance_test_type == DP_TEST_LINK_TRAINING) ||
> + (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count))) {
> + DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
> + intel_encoder->base.name);
> + intel_dp_start_link_train(intel_dp);
> + intel_dp_stop_link_train(intel_dp);
> + }
> +}
> +
> /*
> * According to DP spec
> * 5.1.2:
> @@ -4298,15 +4325,12 @@ go_again:
> * 4. Check link status on receipt of hot-plug interrupt
> */
> static void
> -intel_dp_check_link_status(struct intel_dp *intel_dp)
> +intel_dp_short_pulse(struct intel_dp *intel_dp)
> {
> struct drm_device *dev = intel_dp_to_dev(intel_dp);
> - struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)
> ->base;
> u8 sink_irq_vector;
> u8 link_status[DP_LINK_STATUS_SIZE];
>
> - WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
> -
I think it's better to move this WARN to the new intel_dp_check_link_status().
> /*
> * Clearing compliance test variables to allow capturing
> * of values for next automated test request.
> @@ -4315,12 +4339,6 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
> intel_dp->compliance_test_type = 0;
> intel_dp->compliance_test_data = 0;
>
> - if (!intel_encoder->base.crtc)
> - return;
> -
> - if (!to_intel_crtc(intel_encoder->base.crtc)->active)
> - return;
> -
> /* Try to read receiver status if the link appears to be up */
> if (!intel_dp_get_link_status(intel_dp, link_status)) {
> return;
There is now two calls to intel_dp_get_link_status()and the value of link_status
is not used in this function, so maybe just remove it from here. Looks good
otherwise.
Ander
> @@ -4345,14 +4363,9 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
> DRM_DEBUG_DRIVER("CP or sink specific irq
> unhandled\n");
> }
>
> - /* if link training is requested we should perform it always */
> - if ((intel_dp->compliance_test_type == DP_TEST_LINK_TRAINING) ||
> - (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count))) {
> - DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
> - intel_encoder->base.name);
> - intel_dp_start_link_train(intel_dp);
> - intel_dp_stop_link_train(intel_dp);
> - }
> + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> + intel_dp_check_link_status(intel_dp);
> + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> }
>
> /* XXX this is probably wrong for multiple downstream ports */
> @@ -5080,11 +5093,8 @@ intel_dp_hpd_pulse(struct intel_digital_port
> *intel_dig_port, bool long_hpd)
> }
> }
>
> - if (!intel_dp->is_mst) {
> - drm_modeset_lock(&dev->mode_config.connection_mutex,
> NULL);
> - intel_dp_check_link_status(intel_dp);
> - drm_modeset_unlock(&dev
> ->mode_config.connection_mutex);
> - }
> + if (!intel_dp->is_mst)
> + intel_dp_short_pulse(intel_dp);
> }
>
> ret = IRQ_HANDLED;
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