Re: [PATCH v7 3/3] drm/i915/dp: Expose connector VRR monitor range via debugfs

From: Manasi Navare <manasi.d.navare@intel.com>
To: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	ML dri-devel <dri-devel@lists.freedesktop.org>,
	Bhanuprakash Modem <bhanuprakash.modem@intel.com>
Subject: Re: [PATCH v7 3/3] drm/i915/dp: Expose connector VRR monitor range via debugfs
Date: Thu, 18 Jun 2020 11:35:58 -0700	[thread overview]
Message-ID: <20200618183558.GA32149@intel.com> (raw)
In-Reply-To: <CACvgo51j1BXN2ZyQ-m5AALup3ruoUHZhobSeNfS8QsV-UEjS-Q@mail.gmail.com>

On Tue, Jun 16, 2020 at 04:34:07PM +0100, Emil Velikov wrote:
> On Mon, 15 Jun 2020 at 22:47, Manasi Navare <manasi.d.navare@intel.com> wrote:
> >
> > On Mon, Jun 15, 2020 at 10:36:28PM +0100, Emil Velikov wrote:
> > > Hi Manasi,
> > >
> > > On Sat, 13 Jun 2020 at 00:55, Manasi Navare <manasi.d.navare@intel.com> wrote:
> > > >
> > > > From: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
> > > >
> > > > [Why]
> > > > It's useful to know the min and max vrr range for IGT testing.
> > > >
> > > > [How]
> > > > Expose the min and max vfreq for the connector via a debugfs file
> > > > on the connector, "vrr_range".
> > > >
> > > > Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range
> > > >
> > > > v7:
> > > > * Fix cmpilation due to rebase
> > > > v6:
> > > > * Rebase (manasi)
> > > > v5:
> > > > * Rename to vrr_range to match AMD debugfs
> > > > v4:
> > > > * Rebase
> > > > v3:
> > > > * Remove the unnecessary debug print (Manasi)
> > > > v2:
> > > > * Fix the typo in max_vfreq (Manasi)
> > > > * Change the name of node to i915_vrr_info so we can add
> > > > other vrr info for more debug info (Manasi)
> > > > * Change the VRR capable to display Yes or No (Manasi)
> > > > * Fix indentation checkpatch errors (Manasi)
> > > >
> > > Nit: generally revision log is listed in v2 -> v6 order.
> >
> > Okay point noted. Will update this in the next rev
> >
> > >
> > > > Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
> > > > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > > > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > Tested-by: Manasi Navare <manasi.d.navare@intel.com>
> > > > ---
> > > >  .../drm/i915/display/intel_display_debugfs.c  | 22 ++++++++++++++++++-
> > > >  1 file changed, 21 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > index 28dd717e943a..2921f7d2a26e 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > @@ -2185,6 +2185,21 @@ static const struct file_operations i915_dsc_fec_support_fops = {
> > > >         .write = i915_dsc_fec_support_write
> > > >  };
> > > >
> > > > +static int vrr_range_show(struct seq_file *m, void *data)
> > > > +{
> > > > +       struct drm_connector *connector = m->private;
> > > > +
> > > > +       if (connector->status != connector_status_connected)
> > > > +               return -ENODEV;
> > > > +
> > > > +       seq_printf(m, "Vrr_capable: %s\n", yesno(intel_dp_is_vrr_capable(connector)));
> > > > +       seq_printf(m, "Min: %u\n", (u8)connector->display_info.monitor_range.min_vfreq);
> > > > +       seq_printf(m, "Max: %u\n", (u8)connector->display_info.monitor_range.max_vfreq);
> > > > +
> > > > +       return 0;
> > > > +}
> > > > +DEFINE_SHOW_ATTRIBUTE(vrr_range);
> > > > +
> > > >  /**
> > > >   * intel_connector_debugfs_add - add i915 specific connector debugfs files
> > > >   * @connector: pointer to a registered drm_connector
> > > > @@ -2220,10 +2235,15 @@ int intel_connector_debugfs_add(struct drm_connector *connector)
> > > >         if (INTEL_GEN(dev_priv) >= 10 &&
> > > >             ((connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort &&
> > > >               !to_intel_connector(connector)->mst_port) ||
> > > > -            connector->connector_type == DRM_MODE_CONNECTOR_eDP))
> > > > +            connector->connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > > >                 debugfs_create_file("i915_dsc_fec_support", S_IRUGO, root,
> > > >                                     connector, &i915_dsc_fec_support_fops);
> > > >
> > > > +               if (INTEL_GEN(dev_priv) >= 12)
> > > > +                       debugfs_create_file("vrr_range", S_IRUGO,
> > > > +                                           root, connector, &vrr_range_fops);
> > > > +       }
> > > > +
> > >
> > > I think this should be added by core drm. Ideally drm will add it
> > > automatically for each connector that the driver has called
> > > drm_connector_attach_vrr_capable_property() upon.
> > >
> >
> > But in this case drm_connector_attach_vrr_capable_property() is called by individual
> > driver since its an optional connector property. So we call this inside i915.
> 
> I'm _not_ suggesting that one moves the
> drm_connector_attach_vrr_capable_property() call. Simply create the
> debugfs file in drm itself.
> 
> > Also currently AMD sets this debugfs inside AMD IMO, so setting this here for now.
> Let's do the better thing of a) make drm create the file, and b)
> remove the AMDGPU specific one.
> 
> We're talking about 20-30 lines worth of a patch. Postponing it sounds silly.
> 
> > But I agree that can be moved to drm core may be when drm_display_info gets populated
> > with min and max, thats where drm can add this?
> >
> Both min and max are already part of drm_display_info. On the question
> of how - check the existing properties (edid_override, force) for
> examples.
>

Okay makes sense. Will move the vrr_range to drm debugfs node.
Thanks for your feedback.

Regards
Manasi

> -Emil
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