On Wed, May 15, 2024 at 04:09:23PM +0300, Jani Nikula wrote:
> On Tue, 14 May 2024, Imre Deak <imre.d...@intel.com> wrote:
> > Add connector debugfs entries to set a target link rate/lane count to be
> > used by a link training afterwards. After setting a target link
> > rate/lane count reset the link training parameters and for a non-auto
> > target disable reducing the link parameters via the fallback logic. The
> > former one can be used after testing link training failure scenarios
> > - via debugfs entries added later - to reset the reduced link parameters
> > after the test.
> >
> > Signed-off-by: Imre Deak <imre.d...@intel.com>
> > ---
> > .../drm/i915/display/intel_display_debugfs.c | 218 ++++++++++++++++++
>
> Basically I don't want any new debugfs files to intel_display_debugfs.c.
>
> These should probably go to intel_dp_link_training.c, or maybe
> intel_dp.c or a new intel_dp_debugfs.c. But I think the first.
Ok, forgot about that guidline, both is ok to me. There is a quite a few
DP specific entries, that would call for the latter option.
>
> BR,
> Jani.
>
>
>
> > .../drm/i915/display/intel_display_types.h | 2 +
> > drivers/gpu/drm/i915/display/intel_dp.c | 63 ++++-
> > drivers/gpu/drm/i915/display/intel_dp.h | 2 +
> > .../drm/i915/display/intel_dp_link_training.c | 6 +
> > 5 files changed, 282 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > index 35f9f86ef70f4..521721a20358f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > @@ -1316,6 +1316,215 @@ static const struct file_operations
> > i915_dsc_bpc_fops = {
> > .write = i915_dsc_bpc_write
> > };
> >
> > +static struct intel_dp *intel_connector_to_intel_dp(struct intel_connector
> > *connector)
> > +{
> > + if (connector->mst_port)
> > + return connector->mst_port;
> > + else
> > + return enc_to_intel_dp(intel_attached_encoder(connector));
> > +}
> > +
> > +static int i915_dp_requested_link_rate_show(struct seq_file *m, void *data)
> > +{
> > + struct intel_connector *connector = to_intel_connector(m->private);
> > + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > + struct intel_dp *intel_dp;
> > + int ret;
> > + int i;
> > +
> > + ret =
> > drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);
> > + if (ret)
> > + return ret;
> > +
> > + intel_dp = intel_connector_to_intel_dp(connector);
> > +
> > + seq_printf(m, "%sauto%s",
> > + intel_dp->requested_link_rate == 0 ? "[" : "",
> > + intel_dp->requested_link_rate == 0 ? "]" : "");
> > +
> > + for (i = 0; i < intel_dp->num_source_rates; i++)
> > + seq_printf(m, " %s%d%s%s",
> > + intel_dp->source_rates[i] ==
> > intel_dp->requested_link_rate ? "[" : "",
> > + intel_dp->source_rates[i],
> > + intel_dp->link_trained &&
> > + intel_dp->source_rates[i] ==
> > intel_dp->link_rate ? "*" : "",
> > + intel_dp->source_rates[i] ==
> > intel_dp->requested_link_rate ? "]" : "");
> > +
> > + drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> > +
> > + seq_putc(m, '\n');
> > +
> > + return 0;
> > +}
> > +
> > +static int parse_link_rate(struct intel_dp *intel_dp, const char __user
> > *ubuf, size_t len)
> > +{
> > + char *kbuf;
> > + const char *p;
> > + int rate;
> > + int ret = 0;
> > +
> > + kbuf = memdup_user_nul(ubuf, len);
> > + if (IS_ERR(kbuf))
> > + return PTR_ERR(kbuf);
> > +
> > + p = strim(kbuf);
> > +
> > + if (!strcmp(p, "auto")) {
> > + rate = 0;
> > + } else {
> > + ret = kstrtoint(p, 0, &rate);
> > + if (ret < 0)
> > + goto out_free;
> > +
> > + if (intel_dp_rate_index(intel_dp->source_rates,
> > + intel_dp->num_source_rates,
> > + rate) < 0)
> > + ret = -EINVAL;
> > + }
> > +
> > +out_free:
> > + kfree(kbuf);
> > +
> > + return ret < 0 ? ret : rate;
> > +}
> > +
> > +static ssize_t i915_dp_requested_link_rate_write(struct file *file,
> > + const char __user *ubuf,
> > + size_t len, loff_t *offp)
> > +{
> > + struct seq_file *m = file->private_data;
> > + struct intel_connector *connector = to_intel_connector(m->private);
> > + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > + struct intel_dp *intel_dp = intel_connector_to_intel_dp(connector);
> > + int rate;
> > + int ret;
> > +
> > + ret =
> > drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);
> > + if (ret)
> > + return ret;
> > +
> > + intel_dp = intel_connector_to_intel_dp(connector);
> > +
> > + rate = parse_link_rate(intel_dp, ubuf, len);
> > + if (rate < 0) {
> > + drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> > +
> > + return rate;
> > + }
> > +
> > + intel_dp_reset_link_train_params(intel_dp);
> > + intel_dp->requested_link_rate = rate;
> > +
> > + drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> > +
> > + *offp += len;
> > +
> > + return len;
> > +}
> > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_dp_requested_link_rate);
> > +
> > +static int i915_dp_requested_lane_count_show(struct seq_file *m, void
> > *data)
> > +{
> > + struct intel_connector *connector = to_intel_connector(m->private);
> > + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > + struct intel_dp *intel_dp;
> > + int ret;
> > + int i;
> > +
> > + ret =
> > drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);
> > + if (ret)
> > + return ret;
> > +
> > + intel_dp = intel_connector_to_intel_dp(connector);
> > +
> > + seq_printf(m, "%sauto%s",
> > + intel_dp->requested_lane_count == 0 ? "[" : "",
> > + intel_dp->requested_lane_count == 0 ? "]" : "");
> > +
> > + for (i = 1; i <= 4; i <<= 1)
> > + seq_printf(m, " %s%d%s%s",
> > + i == intel_dp->requested_lane_count ? "[" : "",
> > + i,
> > + intel_dp->link_trained &&
> > + i == intel_dp->lane_count ? "*" : "",
> > + i == intel_dp->requested_lane_count ? "]" : "");
> > +
> > + drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> > +
> > + seq_putc(m, '\n');
> > +
> > + return 0;
> > +}
> > +
> > +static int parse_lane_count(const char __user *ubuf, size_t len)
> > +{
> > + char *kbuf;
> > + const char *p;
> > + int lane_count;
> > + int ret = 0;
> > +
> > + kbuf = memdup_user_nul(ubuf, len);
> > + if (IS_ERR(kbuf))
> > + return PTR_ERR(kbuf);
> > +
> > + p = strim(kbuf);
> > +
> > + if (!strcmp(p, "auto")) {
> > + lane_count = 0;
> > + } else {
> > + ret = kstrtoint(p, 0, &lane_count);
> > + if (ret < 0)
> > + goto out_free;
> > +
> > + switch (lane_count) {
> > + case 1:
> > + case 2:
> > + case 4:
> > + break;
> > + default:
> > + ret = -EINVAL;
> > + }
> > + }
> > +
> > +out_free:
> > + kfree(kbuf);
> > +
> > + return ret < 0 ? ret : lane_count;
> > +}
> > +
> > +static ssize_t i915_dp_requested_lane_count_write(struct file *file,
> > + const char __user *ubuf,
> > + size_t len, loff_t *offp)
> > +{
> > + struct seq_file *m = file->private_data;
> > + struct intel_connector *connector = to_intel_connector(m->private);
> > + struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > + struct intel_dp *intel_dp;
> > + int lane_count;
> > + int ret;
> > +
> > + lane_count = parse_lane_count(ubuf, len);
> > + if (lane_count < 0)
> > + return lane_count;
> > +
> > + ret =
> > drm_modeset_lock_single_interruptible(&i915->drm.mode_config.connection_mutex);
> > + if (ret)
> > + return ret;
> > +
> > + intel_dp = intel_connector_to_intel_dp(connector);
> > +
> > + intel_dp_reset_link_train_params(intel_dp);
> > + intel_dp->requested_lane_count = lane_count;
> > +
> > + drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
> > +
> > + *offp += len;
> > +
> > + return len;
> > +}
> > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_dp_requested_lane_count);
> > +
> > static int i915_dsc_output_format_show(struct seq_file *m, void *data)
> > {
> > struct intel_connector *connector = m->private;
> > @@ -1523,6 +1732,15 @@ void intel_connector_debugfs_add(struct
> > intel_connector *connector)
> > connector, &i915_hdcp_sink_capability_fops);
> > }
> >
> > + if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > + connector_type == DRM_MODE_CONNECTOR_eDP) {
> > + debugfs_create_file("i915_dp_link_rate", 0644, root,
> > + connector,
> > &i915_dp_requested_link_rate_fops);
> > +
> > + debugfs_create_file("i915_dp_lane_count", 0644, root,
> > + connector,
> > &i915_dp_requested_lane_count_fops);
> > + }
> > +
> > if (DISPLAY_VER(i915) >= 11 &&
> > ((connector_type == DRM_MODE_CONNECTOR_DisplayPort &&
> > !connector->mst_port) ||
> > connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index fb71bc7eb3d9a..351c445d3cb5b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1758,6 +1758,8 @@ struct intel_dp {
> > /* intersection of source and sink rates */
> > int num_common_rates;
> > int common_rates[DP_MAX_SUPPORTED_RATES];
> > + int requested_link_rate;
> > + int requested_lane_count;
> > struct {
> > /* Max lane count for the current link */
> > int max_lane_count;
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 5eafda7175e2a..367970f956863 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -345,7 +345,7 @@ int intel_dp_max_common_rate(struct intel_dp *intel_dp)
> > return intel_dp_common_rate(intel_dp, intel_dp->num_common_rates - 1);
> > }
> >
> > -static int intel_dp_max_source_lane_count(struct intel_digital_port
> > *dig_port)
> > +int intel_dp_max_source_lane_count(struct intel_digital_port *dig_port)
> > {
> > int vbt_max_lanes =
> > intel_bios_dp_max_lane_count(dig_port->base.devdata);
> > int max_lanes = dig_port->max_lanes;
> > @@ -371,19 +371,39 @@ int intel_dp_max_common_lane_count(struct intel_dp
> > *intel_dp)
> > return min3(source_max, sink_max, lane_max);
> > }
> >
> > +static int requested_lane_count(struct intel_dp *intel_dp)
> > +{
> > + return clamp(intel_dp->requested_lane_count, 1,
> > intel_dp_max_common_lane_count(intel_dp));
> > +}
> > +
> > int intel_dp_max_lane_count(struct intel_dp *intel_dp)
> > {
> > - switch (intel_dp->link_train.max_lane_count) {
> > + int lane_count;
> > +
> > + if (intel_dp->requested_lane_count)
> > + lane_count = requested_lane_count(intel_dp);
> > + else
> > + lane_count = intel_dp->link_train.max_lane_count;
> > +
> > + switch (lane_count) {
> > case 1:
> > case 2:
> > case 4:
> > - return intel_dp->link_train.max_lane_count;
> > + return lane_count;
> > default:
> > - MISSING_CASE(intel_dp->link_train.max_lane_count);
> > + MISSING_CASE(lane_count);
> > return 1;
> > }
> > }
> >
> > +static int intel_dp_min_lane_count(struct intel_dp *intel_dp)
> > +{
> > + if (intel_dp->requested_lane_count)
> > + return requested_lane_count(intel_dp);
> > +
> > + return 1;
> > +}
> > +
> > /*
> > * The required data bandwidth for a mode with given pixel clock and bpp.
> > This
> > * is the required net bandwidth independent of the data bandwidth
> > efficiency.
> > @@ -1306,16 +1326,38 @@ static void intel_dp_print_rates(struct intel_dp
> > *intel_dp)
> > drm_dbg_kms(&i915->drm, "common rates: %s\n", str);
> > }
> >
> > +static int requested_rate(struct intel_dp *intel_dp)
> > +{
> > + int len = intel_dp_common_len_rate_limit(intel_dp,
> > intel_dp->requested_link_rate);
> > +
> > + if (len == 0)
> > + return intel_dp_common_rate(intel_dp, 0);
> > +
> > + return intel_dp_common_rate(intel_dp, len - 1);
> > +}
> > +
> > int
> > intel_dp_max_link_rate(struct intel_dp *intel_dp)
> > {
> > int len;
> >
> > + if (intel_dp->requested_link_rate)
> > + return requested_rate(intel_dp);
> > +
> > len = intel_dp_common_len_rate_limit(intel_dp,
> > intel_dp->link_train.max_rate);
> >
> > return intel_dp_common_rate(intel_dp, len - 1);
> > }
> >
> > +static int
> > +intel_dp_min_link_rate(struct intel_dp *intel_dp)
> > +{
> > + if (intel_dp->requested_link_rate)
> > + return requested_rate(intel_dp);
> > +
> > + return intel_dp_common_rate(intel_dp, 0);
> > +}
> > +
> > int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
> > {
> > struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > @@ -2285,13 +2327,14 @@ intel_dp_compute_config_limits(struct intel_dp
> > *intel_dp,
> > bool dsc,
> > struct link_config_limits *limits)
> > {
> > - limits->min_rate = intel_dp_common_rate(intel_dp, 0);
> > + limits->min_rate = intel_dp_min_link_rate(intel_dp);
> > limits->max_rate = intel_dp_max_link_rate(intel_dp);
> >
> > /* FIXME 128b/132b SST support missing */
> > limits->max_rate = min(limits->max_rate, 810000);
> > + limits->min_rate = min(limits->min_rate, limits->max_rate);
> >
> > - limits->min_lane_count = 1;
> > + limits->min_lane_count = intel_dp_min_lane_count(intel_dp);
> > limits->max_lane_count = intel_dp_max_lane_count(intel_dp);
> >
> > limits->pipe.min_bpp = intel_dp_min_bpp(crtc_state->output_format);
> > @@ -2307,8 +2350,10 @@ intel_dp_compute_config_limits(struct intel_dp
> > *intel_dp,
> > * configuration, and typically on older panels these
> > * values correspond to the native resolution of the panel.
> > */
> > - limits->min_lane_count = limits->max_lane_count;
> > - limits->min_rate = limits->max_rate;
> > + if (intel_dp->requested_lane_count == 0)
> > + limits->min_lane_count = limits->max_lane_count;
> > + if (intel_dp->requested_link_rate == 0)
> > + limits->min_rate = limits->max_rate;
> > }
> >
> > intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);
> > @@ -2947,7 +2992,7 @@ void intel_dp_set_link_params(struct intel_dp
> > *intel_dp,
> > intel_dp->lane_count = lane_count;
> > }
> >
> > -static void intel_dp_reset_link_train_params(struct intel_dp *intel_dp)
> > +void intel_dp_reset_link_train_params(struct intel_dp *intel_dp)
> > {
> > intel_dp->link_train.max_lane_count =
> > intel_dp_max_common_lane_count(intel_dp);
> > intel_dp->link_train.max_rate = intel_dp_max_common_rate(intel_dp);
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.h
> > b/drivers/gpu/drm/i915/display/intel_dp.h
> > index 7c938327fc725..2b639bb2f56ed 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.h
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> > @@ -95,6 +95,7 @@ void intel_edp_backlight_off(const struct
> > drm_connector_state *conn_state);
> > void intel_edp_fixup_vbt_bpp(struct intel_encoder *encoder, int pipe_bpp);
> > void intel_dp_mst_suspend(struct drm_i915_private *dev_priv);
> > void intel_dp_mst_resume(struct drm_i915_private *dev_priv);
> > +int intel_dp_max_source_lane_count(struct intel_digital_port *dig_port);
> > int intel_dp_max_link_rate(struct intel_dp *intel_dp);
> > int intel_dp_max_lane_count(struct intel_dp *intel_dp);
> > int intel_dp_config_required_rate(const struct intel_crtc_state
> > *crtc_state);
> > @@ -104,6 +105,7 @@ int intel_dp_max_common_lane_count(struct intel_dp
> > *intel_dp);
> > int intel_dp_common_rate(struct intel_dp *intel_dp, int index);
> > int intel_dp_rate_index(const int *rates, int len, int rate);
> > void intel_dp_update_sink_caps(struct intel_dp *intel_dp);
> > +void intel_dp_reset_link_train_params(struct intel_dp *intel_dp);
> >
> > void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
> > u8 *link_bw, u8 *rate_select);
> > 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 b80fb25b9204d..352c77f46015e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > @@ -1114,6 +1114,9 @@ static int reduce_link_rate(struct intel_dp
> > *intel_dp, int current_rate)
> > int rate_index;
> > int new_rate;
> >
> > + if (intel_dp->requested_link_rate)
> > + return -1;
> > +
> > rate_index = intel_dp_rate_index(intel_dp->common_rates,
> > intel_dp->num_common_rates,
> > current_rate);
> > @@ -1132,6 +1135,9 @@ static int reduce_link_rate(struct intel_dp
> > *intel_dp, int current_rate)
> >
> > static int reduce_lane_count(struct intel_dp *intel_dp, int
> > current_lane_count)
> > {
> > + if (intel_dp->requested_lane_count)
> > + return -1;
> > +
> > if (current_lane_count > 1)
> > return current_lane_count >> 1;
>
> --
> Jani Nikula, Intel
