Re: [PATCH v3 6/6] drm/i915/alpm: Add debugfs for LOBF

["Hogander, Jouni" <jouni.hogander@intel.com>]

On Fri, 2024-05-03 at 08:30 +0000, Manna, Animesh wrote:
> 
> 
> > -----Original Message-----
> > From: Hogander, Jouni <jouni.hogander@intel.com>
> > Sent: Friday, May 3, 2024 1:02 PM
> > To: Manna, Animesh <animesh.manna@intel.com>; intel-
> > gfx@lists.freedesktop.org
> > Cc: dri-devel@lists.freedesktop.org; Murthy, Arun R
> > <arun.r.murthy@intel.com>; Nikula, Jani <jani.nikula@intel.com>
> > Subject: Re: [PATCH v3 6/6] drm/i915/alpm: Add debugfs for LOBF
> > 
> > On Thu, 2024-04-25 at 00:08 +0530, Animesh Manna wrote:
> > > For validation purpose add debugfs for LOBF.
> > > 
> > > Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_alpm.c     | 48
> > > +++++++++++++++++++
> > >  drivers/gpu/drm/i915/display/intel_alpm.h     |  2 +
> > >  .../drm/i915/display/intel_display_debugfs.c  |  2 +
> > >  3 files changed, 52 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> > > b/drivers/gpu/drm/i915/display/intel_alpm.c
> > > index b08799586b58..2d3027c2fb0a 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> > > @@ -343,3 +343,51 @@ void intel_alpm_configure(struct intel_dp
> > > *intel_dp,
> > >  {
> > >         lnl_alpm_configure(intel_dp, crtc_state);
> > >  }
> > > +
> > > +static int i915_edp_lobf_info_show(struct seq_file *m, void
> > > *data)
> > > +{
> > > +       struct intel_connector *connector = m->private;
> > > +       struct drm_i915_private *dev_priv = to_i915(connector-
> > > > base.dev);
> > > +       struct drm_crtc *crtc;
> > > +       struct intel_crtc_state *crtc_state;
> > > +       enum transcoder cpu_transcoder;
> > > +       bool lobf_enabled;
> > > +       int ret;
> > > +
> > > +       ret = drm_modeset_lock_single_interruptible(&dev_priv-
> > > > drm.mode_config.connection_mutex);
> > > +       if (ret)
> > > +               return ret;
> > > +
> > > +       crtc = connector->base.state->crtc;
> > > +       if (connector->base.status != connector_status_connected
> > > ||
> > > !crtc) {
> > > +               ret = -ENODEV;
> > > +               goto out;
> > > +       }
> > > +
> > > +       crtc_state = to_intel_crtc_state(crtc->state);
> > > +       seq_printf(m, "LOBF Criteria met: %s\n",
> > > str_yes_no(crtc_state->has_lobf));
> > 
> > I'm still not convinced on this. has_lobf ~= ALPM_CTL_LOBF_ENABLE
> > in
> > ALPM_CTL. To my opinion it is enough to dump seq_printf(m, "LOBF
> > status: %s\n", str_enabled_disabled(lobf_enabled)) below. Maybe
> > AUX_WAKE and AUX_LESS_WAKE could be dumped instead?
> 
> Can add aux-wake or aux-less info as well.
> But as LOBF feature is dependent on adaptive sync fixed refresh rate
> mode (which can be dynamic as per user input) and ALPM. I want to
> expose both the conditions are satisfying or not along with status.

If all those conditions are satisfied (i.e. has_lobf is true) then 
ALPM_CTL & ALPM_CTL_LOBF_ENABLE is true? So I'm wondering what is the
benefit from dumping has_lobf?

BR,

Jouni Högander

> 
> Regards,
> Animesh
>  
> > 
> > BR,
> > 
> > Jouni Högander
> > 
> > > +
> > > +       cpu_transcoder = crtc_state->cpu_transcoder;
> > > +       lobf_enabled = intel_de_read(dev_priv,
> > > ALPM_CTL(cpu_transcoder)) & ALPM_CTL_LOBF_ENABLE;
> > > +       seq_printf(m, "LOBF status: %s\n",
> > > str_enabled_disabled(lobf_enabled));
> > > +
> > > +out:
> > > +       drm_modeset_unlock(&dev_priv-
> > > > drm.mode_config.connection_mutex);
> > > +
> > > +       return ret;
> > > +}
> > > +
> > > +DEFINE_SHOW_ATTRIBUTE(i915_edp_lobf_info);
> > > +
> > > +void intel_alpm_lobf_debugfs_add(struct intel_connector
> > > *connector)
> > > +{
> > > +       struct drm_i915_private *i915 = to_i915(connector-
> > > >base.dev);
> > > +       struct dentry *root = connector->base.debugfs_entry;
> > > +
> > > +       if (DISPLAY_VER(i915) < 20 ||
> > > +           connector->base.connector_type !=
> > DRM_MODE_CONNECTOR_eDP)
> > > +               return;
> > > +
> > > +       debugfs_create_file("i915_edp_lobf_info", 0444, root,
> > > +                           connector, &i915_edp_lobf_info_fops);
> > > +}
> > > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h
> > > b/drivers/gpu/drm/i915/display/intel_alpm.h
> > > index a9ca190da3e4..01fd08eb96f5 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> > > @@ -11,6 +11,7 @@
> > >  struct intel_dp;
> > >  struct intel_crtc_state;
> > >  struct drm_connector_state;
> > > +struct intel_connector;
> > > 
> > >  bool intel_alpm_get_aux_less_status(struct intel_dp *intel_dp);
> > >  bool intel_alpm_compute_params(struct intel_dp *intel_dp,
> > > @@ -20,4 +21,5 @@ void intel_alpm_compute_lobf_config(struct
> > > intel_dp
> > > *intel_dp,
> > >                                     struct drm_connector_state
> > > *conn_state);
> > >  void intel_alpm_configure(struct intel_dp *intel_dp,
> > >                           const struct intel_crtc_state
> > > *crtc_state);
> > > +void intel_alpm_lobf_debugfs_add(struct intel_connector
> > > *connector);
> > >  #endif
> > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > index 35f9f86ef70f..86d9900c40af 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > @@ -13,6 +13,7 @@
> > >  #include "i915_debugfs.h"
> > >  #include "i915_irq.h"
> > >  #include "i915_reg.h"
> > > +#include "intel_alpm.h"
> > >  #include "intel_crtc.h"
> > >  #include "intel_de.h"
> > >  #include "intel_crtc_state_dump.h"
> > > @@ -1515,6 +1516,7 @@ void intel_connector_debugfs_add(struct
> > > intel_connector *connector)
> > >         intel_drrs_connector_debugfs_add(connector);
> > >         intel_pps_connector_debugfs_add(connector);
> > >         intel_psr_connector_debugfs_add(connector);
> > > +       intel_alpm_lobf_debugfs_add(connector);
> > > 
> > >         if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > >             connector_type == DRM_MODE_CONNECTOR_HDMIA ||
>