[Intel-gfx] [PATCH 1/2] drm/i915: Parse DSI backlight/cabc ports.

[Chauhan, Madhav]

> -----Original Message-----
> From: Nikula, Jani
> Sent: Tuesday, October 10, 2017 12:47 PM
> To: Chauhan, Madhav <madhav.chauhan at intel.com>; intel-
> gfx at lists.freedesktop.org
> Cc: Hiremath, Shashidhar <shashidhar.hiremath at intel.com>; Shankar, Uma
> <uma.shankar at intel.com>; Chauhan, Madhav
> <madhav.chauhan at intel.com>
> Subject: Re: [PATCH 1/2] drm/i915: Parse DSI backlight/cabc ports.
> 
> On Tue, 03 Oct 2017, Madhav Chauhan <madhav.chauhan at intel.com>
> wrote:
> > This patch parse DSI backlight/cabc ports info from VBT and save them
> > inside local strucutre. This saved info can be directly used while
> > initializing DSI for different platforms instead of parsing for each
> > platform.
> >
> > Signed-off-by: Madhav Chauhan <madhav.chauhan at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h   |  2 ++
> >  drivers/gpu/drm/i915/intel_bios.c | 63
> > ++++++++++++++++++++++++++++++++-------
> >  2 files changed, 55 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > b/drivers/gpu/drm/i915/i915_drv.h index b7cba89..fc472bb 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1751,6 +1751,8 @@ struct intel_vbt_data {
> >  		u8 seq_version;
> >  		u32 size;
> >  		u8 *data;
> > +		u16 bl_ports;
> > +		u16 cabc_ports;
> 
> This is right in the middle of the sequence data. Please move up e.g. between
> pps and seq_version.

Ok.

> 
> >  		const u8 *sequence[MIPI_SEQ_MAX];
> >  	} dsi;
> >
> > diff --git a/drivers/gpu/drm/i915/intel_bios.c
> > b/drivers/gpu/drm/i915/intel_bios.c
> > index 3747d8d..88a72cc 100644
> > --- a/drivers/gpu/drm/i915/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/intel_bios.c
> > @@ -730,6 +730,56 @@ parse_psr(struct drm_i915_private *dev_priv,
> const struct bdb_header *bdb)
> >  	dev_priv->vbt.psr.tp2_tp3_wakeup_time =
> > psr_table->tp2_tp3_wakeup_time;  }
> >
> > +static void parse_dsi_backlight_ports(struct drm_i915_private *dev_priv,
> > +				      u16 version, enum port port) {
> > +	if (dev_priv->vbt.dsi.config->dual_link && version < 197) {
> > +		/*
> > +		 * These fields are introduced from the VBT version 197
> onwards,
> > +		 * so making sure that these bits are set zero in the previous
> > +		 * versions.
> > +		 */
> > +		dev_priv->vbt.dsi.config->dl_dcs_cabc_ports = 0;
> > +		dev_priv->vbt.dsi.config->dl_dcs_backlight_ports = 0;
> 
> You could remove this in patch 2. Nobody should be looking at it anymore.

Patch 2 means?? Next version of this patch or patch 2 of this series.
Patch 2 of this series doesn't use these variables. Please clarify.

> 
> > +		dev_priv->vbt.dsi.bl_ports = 0;
> > +		dev_priv->vbt.dsi.cabc_ports = 0;
> 
> This you don't have to do anyway, it's all zeros by default.

Ok.

> 
> > +		return;
> > +	} else if (dev_priv->vbt.dsi.config->dual_link) {
> > +		switch (dev_priv->vbt.dsi.config->dl_dcs_backlight_ports) {
> > +		case DL_DCS_PORT_A:
> > +			dev_priv->vbt.dsi.bl_ports = BIT(PORT_A);
> > +			break;
> > +		case DL_DCS_PORT_C:
> > +			dev_priv->vbt.dsi.bl_ports = BIT(PORT_C);
> > +			break;
> > +		default:
> > +		case DL_DCS_PORT_A_AND_C:
> > +			dev_priv->vbt.dsi.bl_ports = BIT(PORT_A) |
> BIT(PORT_C);
> > +			break;
> > +		}
> > +
> > +		switch (dev_priv->vbt.dsi.config->dl_dcs_cabc_ports) {
> > +		case DL_DCS_PORT_A:
> > +			dev_priv->vbt.dsi.cabc_ports = BIT(PORT_A);
> > +			break;
> > +		case DL_DCS_PORT_C:
> > +			dev_priv->vbt.dsi.cabc_ports = BIT(PORT_C);
> > +			break;
> > +		default:
> > +		case DL_DCS_PORT_A_AND_C:
> > +			dev_priv->vbt.dsi.cabc_ports =
> > +						BIT(PORT_A) | BIT(PORT_C);
> > +			break;
> > +		}
> > +	} else {
> > +		dev_priv->vbt.dsi.bl_ports = BIT(port);
> > +		dev_priv->vbt.dsi.cabc_ports = BIT(port);
> > +	}
> > +
> > +	if (!dev_priv->vbt.dsi.config->cabc_supported)
> > +		dev_priv->vbt.dsi.cabc_ports = 0;
> 
> Would seem reasonable to not initalize it in the first place if it's not
> supported. 

Agree. How about putting a check condition !cabc_supported
before parsing dl_dcs_cabc_ports in switch case??

>If you do a series of early returns starting with the bdb version
> check, then !dual_link, then !cabc_supported, it might be easiest.

But even if for !dual_link, still we need to fill newly added cabc_ports and bl_ports.

Regards,
Madhav

> 
> > +}
> > +
> >  static void
> >  parse_mipi_config(struct drm_i915_private *dev_priv,
> >  		  const struct bdb_header *bdb)
> > @@ -738,9 +788,10 @@ parse_mipi_config(struct drm_i915_private
> *dev_priv,
> >  	const struct mipi_config *config;
> >  	const struct mipi_pps_data *pps;
> >  	int panel_type = dev_priv->vbt.panel_type;
> > +	enum port port;
> >
> >  	/* parse MIPI blocks only if LFP type is MIPI */
> > -	if (!intel_bios_is_dsi_present(dev_priv, NULL))
> > +	if (!intel_bios_is_dsi_present(dev_priv, &port))
> >  		return;
> >
> >  	/* Initialize this to undefined indicating no generic MIPI support
> > */ @@ -781,15 +832,7 @@ parse_mipi_config(struct drm_i915_private
> *dev_priv,
> >  		return;
> >  	}
> >
> > -	/*
> > -	 * These fields are introduced from the VBT version 197 onwards,
> > -	 * so making sure that these bits are set zero in the previous
> > -	 * versions.
> > -	 */
> > -	if (dev_priv->vbt.dsi.config->dual_link && bdb->version < 197) {
> > -		dev_priv->vbt.dsi.config->dl_dcs_cabc_ports = 0;
> > -		dev_priv->vbt.dsi.config->dl_dcs_backlight_ports = 0;
> > -	}
> > +	parse_dsi_backlight_ports(dev_priv, bdb->version, port);
> >
> >  	/* We have mandatory mipi config blocks. Initialize as generic panel
> */
> >  	dev_priv->vbt.dsi.panel_id = MIPI_DSI_GENERIC_PANEL_ID;
> 
> --
> Jani Nikula, Intel Open Source Technology Center