Re: [Intel-gfx] [PATCH v3 5/5] drm/i915/vbt: Parse power conservation features block

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 04 Dec 2019, "Souza, Jose" <jose.souza@intel.com> wrote:
> On Thu, 2019-11-28 at 16:29 +0200, Jani Nikula wrote:
>> On Wed, 27 Nov 2019, José Roberto de Souza <jose.souza@intel.com>
>> wrote:
>> > From VBT 228+ this is block that PSR and other power saving
>> > features configuration should be read from.
>> > 
>> > v3:
>> > Using DRRS from this new block
>> > 
>> > Cc: Matt Roper <matthew.d.roper@intel.com>
>> > Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
>> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_bios.c     | 36
>> > +++++++++++++++++--
>> >  drivers/gpu/drm/i915/display/intel_vbt_defs.h | 29 +++++++++++++++
>> >  2 files changed, 62 insertions(+), 3 deletions(-)
>> > 
>> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c
>> > b/drivers/gpu/drm/i915/display/intel_bios.c
>> > index f6a9a5ccb556..2d06f1f5734d 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_bios.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c
>> > @@ -659,16 +659,45 @@ parse_driver_features(struct drm_i915_private
>> > *dev_priv,
>> >  			dev_priv->vbt.int_lvds_support = 0;
>> >  	}
>> >  
>> > -	DRM_DEBUG_KMS("DRRS State Enabled:%d\n", driver->drrs_enabled);
>> > +	if (bdb->version < 228) {
>> > +		DRM_DEBUG_KMS("DRRS State Enabled:%d\n", driver-
>> > >drrs_enabled);
>> > +		/*
>> > +		 * If DRRS is not supported, drrs_type has to be set to
>> > 0.
>> > +		 * This is because, VBT is configured in such a way
>> > that
>> > +		 * static DRRS is 0 and DRRS not supported is
>> > represented by
>> > +		 * driver->drrs_enabled=false
>> > +		 */
>> > +		if (!driver->drrs_enabled)
>> > +			dev_priv->vbt.drrs_type = DRRS_NOT_SUPPORTED;
>> > +
>> > +		dev_priv->vbt.psr.enable = driver->psr_enabled;
>> > +	}
>> > +}
>> 
>> Maybe this review comment gives you an idea what we have to think of
>> and
>> deal with when working with VBT and VBT parsing.
>> 
>> Imagine VBT version >= 228 without lvds power block, and
>> driver->drrs_enabled == false.
>
> That happened in the past with other obsolete blocks?
> If not I guess we should trust VBT and not try to over handled this
> cases that might never happen.

I think maybe you should spend some more time fixing end user reported
bugs that involve the VBT out in the real world. ;)

BR,
Jani.

>
> VBT versions 228 will be used in TGL+ that supports more than one eDP
> panel so this global DRRS/PSR disable would be applied to all eDP
> panels? (When we support more than one instance of PSR and DRRS)
>
>> 
>> > +
>> > +static void
>> > +parse_power_conservation_features(struct drm_i915_private
>> > *dev_priv,
>> > +				  const struct bdb_header *bdb)
>> > +{
>> > +	const struct bdb_lfp_power *power;
>> > +	u8 panel_type = dev_priv->vbt.panel_type;
>> > +
>> > +	if (bdb->version < 228)
>> > +		return;
>> > +
>> > +	power = find_section(bdb, BDB_LVDS_POWER);
>> > +	if (!power)
>> > +		return;
>> > +
>> > +	dev_priv->vbt.psr.enable = power->psr & (1 << panel_type);
>> > +
>> >  	/*
>> >  	 * If DRRS is not supported, drrs_type has to be set to 0.
>> >  	 * This is because, VBT is configured in such a way that
>> >  	 * static DRRS is 0 and DRRS not supported is represented by
>> >  	 * driver->drrs_enabled=false
>> >  	 */
>> > -	if (!driver->drrs_enabled)
>> > +	if (!(power->drrs & (1 << panel_type)))
>> >  		dev_priv->vbt.drrs_type = DRRS_NOT_SUPPORTED;
>> > -	dev_priv->vbt.psr.enable = driver->psr_enabled;
>> >  }
>> >  
>> >  static void
>> > @@ -1973,6 +2002,7 @@ void intel_bios_init(struct drm_i915_private
>> > *dev_priv)
>> >  	parse_lfp_backlight(dev_priv, bdb);
>> >  	parse_sdvo_panel_data(dev_priv, bdb);
>> >  	parse_driver_features(dev_priv, bdb);
>> > +	parse_power_conservation_features(dev_priv, bdb);
>> >  	parse_edp(dev_priv, bdb);
>> >  	parse_psr(dev_priv, bdb);
>> >  	parse_mipi_config(dev_priv, bdb);
>> > diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
>> > b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
>> > index f0338da3a82a..98b71dc32d2a 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
>> > +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
>> > @@ -793,6 +793,35 @@ struct bdb_lfp_backlight_data {
>> >  	struct lfp_backlight_control_method backlight_control[16];
>> >  } __packed;
>> >  
>> > +/*
>> > + * Block 44 - LFP Power Conservation Features Block
>> > + */
>> > +
>> > +struct als_data_entry {
>> > +	u16 backlight_adjust;
>> > +	u16 lux;
>> > +} __packed;
>> > +
>> > +struct agressiveness_profile_entry {
>> > +	u8 dpst_agressiveness : 4;
>> > +	u8 lace_agressiveness : 4;
>> 
>> Nitpick, none of the other bitfields have spaces around : here.
>> 
>> > +} __packed;
>> > +
>> > +struct bdb_lfp_power {
>> 
>> The idea is that the bdb struct name is the same as the block id
>> enum,
>> just lower case. Please fix either.
>
> Will fix the block id to match BSpec.
>
>> 
>> BR,
>> Jani.
>> 
>> 
>> > +	u8 lfp_feature_bits;
>> > +	struct als_data_entry als[5];
>> > +	u8 lace_aggressiveness_profile;
>> > +	u16 dpst;
>> > +	u16 psr;
>> > +	u16 drrs;
>> > +	u16 lace_support;
>> > +	u16 adt;
>> > +	u16 dmrrs;
>> > +	u16 adb;
>> > +	u16 lace_enabled_status;
>> > +	struct agressiveness_profile_entry aggressivenes[16];
>> > +} __packed;
>> > +
>> >  /*
>> >   * Block 52 - MIPI Configuration Block
>> >   */

-- 
Jani Nikula, Intel Open Source Graphics Center
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