Re: [PATCH v5 2/2] drm/edid: Add function to parse EDID descriptors for adaptive sync limits

[Manasi Navare <manasi.d.navare@intel.com>]

On Tue, Mar 10, 2020 at 09:13:30PM +0200, Ville Syrjälä wrote:
> On Tue, Mar 10, 2020 at 12:08:33PM -0700, Manasi Navare wrote:
> > Hi Ville,
> > 
> > Please find answers to your concerns below:
> > 
> > On Mon, Mar 09, 2020 at 02:39:40PM -0700, Manasi Navare wrote:
> > > Adaptive Sync is a VESA feature so add a DRM core helper to parse
> > > the EDID's detailed descritors to obtain the adaptive sync monitor range.
> > > Store this info as part fo drm_display_info so it can be used
> > > across all drivers.
> > > This part of the code is stripped out of amdgpu's function
> > > amdgpu_dm_update_freesync_caps() to make it generic and be used
> > > across all DRM drivers
> > > 
> > > v5:
> > > * Use the renamed flags
> > > v4:
> > > * Use is_display_descriptor() (Ville)
> > > * Name the monitor range flags (Ville)
> > > v3:
> > > * Remove the edid parsing restriction for just DP (Nicholas)
> > > * Use drm_for_each_detailed_block (Ville)
> > > * Make the drm_get_adaptive_sync_range function static (Harry, Jani)
> > > v2:
> > > * Change vmin and vmax to use u8 (Ville)
> > > * Dont store pixel clock since that is just a max dotclock
> > > and not related to VRR mode (Manasi)
> > > 
> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Cc: Harry Wentland <harry.wentland@amd.com>
> > > Cc: Clinton A Taylor <clinton.a.taylor@intel.com>
> > > Cc: Kazlauskas Nicholas <Nicholas.Kazlauskas@amd.com>
> > > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > > Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
> > > ---
> > >  drivers/gpu/drm/drm_edid.c  | 44 +++++++++++++++++++++++++++++++++++++
> > >  include/drm/drm_connector.h | 22 +++++++++++++++++++
> > >  2 files changed, 66 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > > index ad41764a4ebe..24b76ae58fdd 100644
> > > --- a/drivers/gpu/drm/drm_edid.c
> > > +++ b/drivers/gpu/drm/drm_edid.c
> > > @@ -4938,6 +4938,47 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
> > >  	}
> > >  }
> > >  
> > > +static
> > > +void get_adaptive_sync_range(struct detailed_timing *timing,
> > > +			     void *info_adaptive_sync)
> > > +{
> > > +	struct drm_adaptive_sync_info *adaptive_sync = info_adaptive_sync;
> > > +	const struct detailed_non_pixel *data = &timing->data.other_data;
> > > +	const struct detailed_data_monitor_range *range = &data->data.range;
> > > +
> > > +	if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_MONITOR_RANGE))
> > > +		return;
> > > +
> > > +	/*
> > > +	 * Check for flag range limits only. If flag == 1 then
> > > +	 * no additional timing information provided.
> > > +	 * Default GTF, GTF Secondary curve and CVT are not
> > > +	 * supported
> > > +	 */
> > > +	if (range->flags != DRM_EDID_RANGE_LIMITS_ONLY_FLAG)
> > > +		return;
> > > +
> > > +	adaptive_sync->min_vfreq = range->min_vfreq;
> > > +	adaptive_sync->max_vfreq = range->max_vfreq;
> > > +}
> > > +
> > > +static
> > > +void drm_get_adaptive_sync_range(struct drm_connector *connector,
> > > +				 const struct edid *edid)
> > > +{
> > > +	struct drm_display_info *info = &connector->display_info;
> > > +
> > > +	if (!version_greater(edid, 1, 1))
> > > +		return;
> > > +
> > > +	drm_for_each_detailed_block((u8 *)edid, get_adaptive_sync_range,
> > > +				    &info->adaptive_sync);
> > 
> > Some functions like get_monitor_name also pass something like &edid_name, I dont
> > think there is any specific convention of the argument name to be passed.
> 
> Hmm. Yeah, it's a bit all over. Still I'd probably follow 
> the majority vote.
>

I feel that this name makes it more intuitive rather than adding a generic name
If you dont feel strongly about changing it, I would like to keep this as is
 
> > 
> > > +
> > > +	DRM_DEBUG_KMS("Adaptive Sync refresh rate range is %d Hz - %d Hz\n",
> > > +		      info->adaptive_sync.min_vfreq,
> > > +		      info->adaptive_sync.max_vfreq);
> > 
> > Yes I agree that this is just a monitor range and unless the dpcd ignore msa bit is set
> > and the range is atleast 10Hz apart , it might not be vrr range.
> > 
> > Would you prefer renaming this info->adaptive_sync as info->monitor_range ? Or
> > should i just print it out as Monitor range is in the dmesg but leave the info->adaptive_sync
> > naming as is?
> 
> If we want to parse it uncoditionally then I guess I'd go with the
> monitor_rage naming, and leave it up to the vrr code to know what to do
> with it.
>

Yes I plan to add a function in the driver code that checks for the msa bit and this range to be
greater than 10 to say that the sink is adaptive sync capable.

So i will just rename this struct to monitor range then?

Manasi 
> > 
> > Manasi
> > 
> > > +}
> > > +
> > >  /* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset
> > >   * all of the values which would have been set from EDID
> > >   */
> > > @@ -4960,6 +5001,7 @@ drm_reset_display_info(struct drm_connector *connector)
> > >  	memset(&info->hdmi, 0, sizeof(info->hdmi));
> > >  
> > >  	info->non_desktop = 0;
> > > +	memset(&info->adaptive_sync, 0, sizeof(info->adaptive_sync));
> > >  }
> > >  
> > >  u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid)
> > > @@ -4975,6 +5017,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
> > >  
> > >  	info->non_desktop = !!(quirks & EDID_QUIRK_NON_DESKTOP);
> > >  
> > > +	drm_get_adaptive_sync_range(connector, edid);
> > > +
> > >  	DRM_DEBUG_KMS("non_desktop set to %d\n", info->non_desktop);
> > >  
> > >  	if (edid->revision < 3)
> > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > > index 0df7a95ca5d9..2b22c0fa42c4 100644
> > > --- a/include/drm/drm_connector.h
> > > +++ b/include/drm/drm_connector.h
> > > @@ -254,6 +254,23 @@ enum drm_panel_orientation {
> > >  	DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
> > >  };
> > >  
> > > +/**
> > > + * struct drm_adaptive_sync_info - Panel's Adaptive Sync capabilities for
> > > + * &drm_display_info
> > > + *
> > > + * This struct is used to store a Panel's Adaptive Sync capabilities
> > > + * as parsed from EDID's detailed monitor range descriptor block.
> > > + *
> > > + * @min_vfreq: This is the min supported refresh rate in Hz from
> > > + *             EDID's detailed monitor range.
> > > + * @max_vfreq: This is the max supported refresh rate in Hz from
> > > + *             EDID's detailed monitor range
> > > + */
> > > +struct drm_adaptive_sync_info {
> > > +	u8 min_vfreq;
> > > +	u8 max_vfreq;
> > > +};
> > > +
> > >  /*
> > >   * This is a consolidated colorimetry list supported by HDMI and
> > >   * DP protocol standard. The respective connectors will register
> > > @@ -473,6 +490,11 @@ struct drm_display_info {
> > >  	 * @non_desktop: Non desktop display (HMD).
> > >  	 */
> > >  	bool non_desktop;
> > > +
> > > +	/**
> > > +	 * @adaptive_sync: Adaptive Sync capabilities of the DP/eDP sink
> > > +	 */
> > > +	struct drm_adaptive_sync_info adaptive_sync;
> > >  };
> > >  
> > >  int drm_display_info_set_bus_formats(struct drm_display_info *info,
> > > -- 
> > > 2.19.1
> > > 
> 
> -- 
> Ville Syrjälä
> Intel
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel