Re: [PATCH 6/9] drm/i915/bxt: Fix BXT DSI disable sequence

From: "Srinivas, Vidya" <vidya.srinivas@intel.com>
To: "Paauwe, Bob J" <bob.j.paauwe@intel.com>
Cc: "Nikula, Jani" <jani.nikula@intel.com>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 6/9] drm/i915/bxt: Fix BXT DSI disable sequence
Date: Mon, 20 Feb 2017 09:39:34 +0000	[thread overview]
Message-ID: <F653A0A18852B74D88578FA2EB7094EA8B50621E@BGSMSX108.gar.corp.intel.com> (raw)
In-Reply-To: <20170215102433.259213e0@bpaauwe-desk.fm.intel.com>

> -----Original Message-----
> From: Paauwe, Bob J
> Sent: Wednesday, February 15, 2017 11:55 PM
> To: Srinivas, Vidya <vidya.srinivas@intel.com>
> Cc: intel-gfx@lists.freedesktop.org; Nikula, Jani <jani.nikula@intel.com>
> Subject: Re: [Intel-gfx] [PATCH 6/9] drm/i915/bxt: Fix BXT DSI disable
> sequence
> 
> On Wed, 8 Feb 2017 16:20:55 +0530
> Vidya Srinivas <vidya.srinivas@intel.com> wrote:
> 
> > From: Uma Shankar <uma.shankar@intel.com>
> >
> > Fix BXT DSI disable sequence as per latest updates in BSpec.
> >
> > Signed-off-by: Uma Shankar <uma.shankar@intel.com>
> > Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dsi.c | 29 +++++++++++++++++++++++++----
> >  1 file changed, 25 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c
> > b/drivers/gpu/drm/i915/intel_dsi.c
> > index 538755b..808158f 100644
> > --- a/drivers/gpu/drm/i915/intel_dsi.c
> > +++ b/drivers/gpu/drm/i915/intel_dsi.c
> > @@ -632,8 +632,10 @@ static void intel_dsi_disable(struct intel_encoder
> *encoder)
> >  		for_each_dsi_port(port, intel_dsi->ports)
> >  			wait_for_dsi_fifo_empty(intel_dsi, port);
> >
> > -		intel_dsi_port_disable(encoder);
> > -		msleep(2);
> > +		if (!IS_BROXTON(dev_priv)) {
> > +			intel_dsi_port_disable(encoder);
> > +			usleep_range(2000, 2500);
> > +		}
> >  	}
> >
> >  	for_each_dsi_port(port, intel_dsi->ports) { @@ -641,7 +643,11 @@
> > static void intel_dsi_disable(struct intel_encoder *encoder)
> >  		I915_WRITE(MIPI_DEVICE_READY(port), 0x0);
> >
> >  		intel_dsi_reset_clocks(encoder, port);
> > -		I915_WRITE(MIPI_EOT_DISABLE(port), CLOCKSTOP);
> > +		temp = 0;
> > +		if (intel_dsi->clock_stop) {
> > +			temp |= CLOCKSTOP;
> > +			I915_WRITE(MIPI_EOT_DISABLE(port), temp);
> > +		}
> 
> This could be simplified to just
> 		if (intel_dsi->clock_stop)
> 			I915_WRITE(MIPI_EOT_DISABLE(port), CLOCKSTOP);
> 
Yes, thanks Bob. I will fix this and resend.

> >
> >  		temp = I915_READ(MIPI_DSI_FUNC_PRG(port));
> >  		temp &= ~VID_MODE_FORMAT_MASK;
> > @@ -707,12 +713,25 @@ static void intel_dsi_post_disable(struct
> intel_encoder *encoder,
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> >  	u32 val;
> > +	enum port port;
> >
> >  	DRM_DEBUG_KMS("\n");
> >
> >  	intel_dsi_disable(encoder);
> >
> > -	intel_dsi_clear_device_ready(encoder);
> > +	if (IS_BROXTON(dev_priv)) {
> > +		/*
> > +		 * Reset the DSI Device ready first for both ports
> > +		 * and then port control registers for both ports
> > +		 */
> > +		for_each_dsi_port(port, intel_dsi->ports)
> > +			I915_WRITE(MIPI_DEVICE_READY(port), 0);
> > +
> > +		for_each_dsi_port(port, intel_dsi->ports)
> > +			I915_WRITE(BXT_MIPI_PORT_CTRL(port), 0);
> > +	} else {
> > +		intel_dsi_clear_device_ready(encoder);
> > +	}
> >
> >  	if (IS_BROXTON(dev_priv)) {
> >  		/* Power down DSI regulator to save power */ @@ -737,6
> +756,8 @@
> > static void intel_dsi_post_disable(struct intel_encoder *encoder,
> >
> >  	drm_panel_unprepare(intel_dsi->panel);
> >
> > +	/* Disable Panel */
> > +	drm_panel_power_off(intel_dsi->panel);
> 
> This depends on the previous patch, which I don't think is the direction we
> want to go.  If the code is reworked to not use the drm_panel interface, then
> this would need to change also.
> 
Yes, I am planning a different approach to remove the drm_panel interface
Dependency. Will re-submit an updated series.

Thanks Bob for the review and useful comments.

Regards
Vidya

> >  	msleep(intel_dsi->panel_off_delay);
> >
> 
> Do we need to call intel_disable_dsi_pll(encoder) here as part of the power
> off?
> 
> >  	/* Panel Disable over CRC PMIC */
> 
> 
> 
> --
> --
> Bob Paauwe
> Bob.J.Paauwe@intel.com
> IOTG / PED Software Organization
> Intel Corp.  Folsom, CA
> (916) 356-6193

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