Re: [Intel-gfx] [V12 4/4] drm/i915/dsi: Initiate fame request in cmd mode

["Kulkarni, Vandita" <vandita.kulkarni@intel.com>]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Sent: Thursday, September 17, 2020 5:01 PM
> To: Kulkarni, Vandita <vandita.kulkarni@intel.com>
> Cc: intel-gfx@lists.freedesktop.org; Nikula, Jani <jani.nikula@intel.com>; B S,
> Karthik <karthik.b.s@intel.com>
> Subject: Re: [V12 4/4] drm/i915/dsi: Initiate fame request in cmd mode
> 
> On Wed, Sep 16, 2020 at 09:45:28PM +0530, Vandita Kulkarni wrote:
> > In TE Gate mode or TE NO_GATE mode on every flip we need to set the
> > frame update request bit.
> > After this  bit is set transcoder hardware will automatically send the
> > frame data to the panel in case of TE NO_GATE mode, where it sends
> > after it receives the TE event in case of TE_GATE mode.
> > Once the frame data is sent to the panel, we see the frame counter
> > updating.
> >
> > v2: Use intel_de_read/write
> >
> > v3: remove the usage of private_flags
> >
> > v4: Use icl_dsi in func names if non static,
> >     fix code formatting issues. (Jani)
> >
> > Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/icl_dsi.c       | 26 ++++++++++++++++++++
> >  drivers/gpu/drm/i915/display/intel_display.c | 10 ++++++++
> >  drivers/gpu/drm/i915/display/intel_dsi.h     |  1 +
> >  3 files changed, 37 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c
> > b/drivers/gpu/drm/i915/display/icl_dsi.c
> > index 2789020e20db..7d2abc7f6ba3 100644
> > --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> > +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> > @@ -205,6 +205,32 @@ static int dsi_send_pkt_payld(struct intel_dsi_host
> *host,
> >  	return 0;
> >  }
> >
> > +void icl_dsi_frame_update(struct intel_crtc_state *crtc_state) {
> > +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > +	u32 tmp, flags;
> > +	enum port port;
> > +
> > +	flags = crtc->mode_flags;
> > +
> > +	/*
> > +	 * case 1 also covers dual link
> > +	 * In case of dual link, frame update should be set on
> > +	 * DSI_0
> > +	 */
> > +	if (flags & I915_MODE_FLAG_DSI_USE_TE0)
> > +		port = PORT_A;
> > +	else if (flags & I915_MODE_FLAG_DSI_USE_TE1)
> > +		port = PORT_B;
> > +	else
> > +		return;
> > +
> > +	tmp = intel_de_read(dev_priv, DSI_CMD_FRMCTL(port));
> > +	tmp |= DSI_FRAME_UPDATE_REQUEST;
> > +	intel_de_write(dev_priv, DSI_CMD_FRMCTL(port), tmp); }
> > +
> >  static void dsi_program_swing_and_deemphasis(struct intel_encoder
> > *encoder)  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> diff
> > --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index f862403388f6..11a20bf2255f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -15621,6 +15621,16 @@ static void intel_atomic_commit_tail(struct
> intel_atomic_state *state)
> >  		intel_set_cdclk_post_plane_update(state);
> >  	}
> >
> > +	/*
> > +	 * Incase of mipi dsi command mode, we need to set frame update
> > +	 * for every commit
> > +	 */
> > +	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i)
> > +		if (INTEL_GEN(dev_priv) >= 11 &&
> > +		    intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI))
> > +			if (new_crtc_state->hw.active)
> > +				icl_dsi_frame_update(new_crtc_state);
> 
> If this is the thing that triggers the update then it should probably be called at
> the start of intel_pipe_update_end().

I could move it to the end of intel_pipe_update_end, as we need TE to be enabled.
Because if the frame updates are gated then, the dsi controller will not drive the vblank/ frame start to the display engine
until it receives a TE in the presence of the frame update request.
And if we are in non gated mode then the dsi controller will immediately drive the vblank/frame strart as soon as it receives the
frame update request.

So is it ok if I move it to the end of pipe_update_end..

Thanks,
Vandita
> 
> > +
> >  	/* FIXME: We should call drm_atomic_helper_commit_hw_done()
> here
> >  	 * already, but still need the state for the delayed optimization. To
> >  	 * fix this:
> > diff --git a/drivers/gpu/drm/i915/display/intel_dsi.h
> > b/drivers/gpu/drm/i915/display/intel_dsi.h
> > index 19f78a4022d3..625f2f1ae061 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dsi.h
> > +++ b/drivers/gpu/drm/i915/display/intel_dsi.h
> > @@ -167,6 +167,7 @@ static inline u16 intel_dsi_encoder_ports(struct
> > intel_encoder *encoder)
> >
> >  /* icl_dsi.c */
> >  void icl_dsi_init(struct drm_i915_private *dev_priv);
> > +void icl_dsi_frame_update(struct intel_crtc_state *crtc_state);
> >
> >  /* intel_dsi.c */
> >  int intel_dsi_bitrate(const struct intel_dsi *intel_dsi);
> > --
> > 2.21.0.5.gaeb582a
> 
> --
> Ville Syrjälä
> Intel
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