Re: [RFC 4/7] drm/i915/dsi: Helper to find dsi encoder in cmd mode

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

On Wed, 16 Oct 2019, "Kulkarni, Vandita" <vandita.kulkarni@intel.com> wrote:
>> -----Original Message-----
>> From: Nikula, Jani <jani.nikula@intel.com>
>> Sent: Wednesday, October 16, 2019 12:51 AM
>> To: Kulkarni, Vandita <vandita.kulkarni@intel.com>; intel-
>> gfx@lists.freedesktop.org
>> Cc: ville.syrjala@linux.intel.com; Shankar, Uma <uma.shankar@intel.com>;
>> Chauhan, Madhav <madhav.chauhan@intel.com>; Kulkarni, Vandita
>> <vandita.kulkarni@intel.com>
>> Subject: Re: [RFC 4/7] drm/i915/dsi: Helper to find dsi encoder in cmd mode
>> 
>> On Mon, 14 Oct 2019, Vandita Kulkarni <vandita.kulkarni@intel.com> wrote:
>> > From: Madhav Chauhan <madhav.chauhan@intel.com>
>> >
>> > This patch adds a helper function to find encoder if DSI is operating
>> > in command mode. This function will be used while enabling/disabling
>> > TE interrupts for DSI.
>> >
>> > Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
>> > Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/icl_dsi.c   | 17 +++++++++++++++++
>> >  drivers/gpu/drm/i915/display/intel_dsi.h |  3 +++
>> >  2 files changed, 20 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c
>> > b/drivers/gpu/drm/i915/display/icl_dsi.c
>> > index 5dd9eebab6b1..877746416e52 100644
>> > --- a/drivers/gpu/drm/i915/display/icl_dsi.c
>> > +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
>> > @@ -73,6 +73,23 @@ static enum transcoder
>> dsi_port_to_transcoder(enum port port)
>> >  		return TRANSCODER_DSI_1;
>> >  }
>> >
>> > +struct intel_encoder *gen11_dsi_find_cmd_mode_encoder(struct
>> > +intel_crtc *crtc) {
>> > +	struct drm_device *dev = crtc->base.dev;
>> > +	struct intel_encoder *encoder;
>> > +	struct intel_dsi *intel_dsi;
>> > +
>> > +	for_each_encoder_on_crtc(dev, &crtc->base, encoder) {
>> > +		if (encoder->type != INTEL_OUTPUT_DSI)
>> > +			continue;
>> > +		intel_dsi = enc_to_intel_dsi(&encoder->base);
>> > +		if (intel_dsi->operation_mode ==
>> INTEL_DSI_COMMAND_MODE)
>> > +			return encoder;
>> > +	}
>> > +
>> > +	return NULL;
>> > +}
>> 
>> This may be a bit harsh, but everything that feels wrong about the following
>> patches pretty much boils down to this function. It may get the job done,
>> and I don't have a better suggestion on how to accomplish this right now.
>> But it seems like we shouldn't have to do anything like this, and makes you
>> feel like there's something wrong with the design.
>> 
>> It would be great to be able to handle this using crtc state, but alas the
>> vblank enable hook only gets passed a struct drm_crtc *. (Patch 7 could
>> easily switch to using crtc state, but need to also solve patch
>> 5.)
> .
>> 
>> I'll get back to you on this later, but in the mean time - Ville, do you have
>> any ideas?
>
> Other option of adding in crtc_state, did you mean something like this
> https://patchwork.freedesktop.org/patch/336178/ 
> @Jani and @Ville  Please let me know your comments.

The problem is that we don't have access to the crtc state in patch 5
gen11_dsi_configure_te() because the call path is via drm_crtc_funcs and
bdw_enable_vblank.

BR,
Jani.


>
> Thanks,
> Vandita
>> 
>> 
>> BR,
>> Jani.
>> 
>> 
>> > +
>> >  static void wait_for_cmds_dispatched_to_panel(struct intel_encoder
>> > *encoder)  {
>> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); diff
>> > --git a/drivers/gpu/drm/i915/display/intel_dsi.h
>> > b/drivers/gpu/drm/i915/display/intel_dsi.h
>> > index b15be5814599..071dad7ee04a 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dsi.h
>> > +++ b/drivers/gpu/drm/i915/display/intel_dsi.h
>> > @@ -201,6 +201,9 @@ u32 bxt_dsi_get_pclk(struct intel_encoder
>> *encoder,
>> >  		     struct intel_crtc_state *config);  void
>> > bxt_dsi_reset_clocks(struct intel_encoder *encoder, enum port port);
>> >
>> > +/* icl_dsi.c */
>> > +struct intel_encoder *gen11_dsi_find_cmd_mode_encoder(struct
>> > +intel_crtc *crtc);
>> > +
>> >  /* intel_dsi_vbt.c */
>> >  bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id);
>> > void intel_dsi_vbt_exec_sequence(struct intel_dsi *intel_dsi,
>> 
>> --
>> Jani Nikula, Intel Open Source Graphics Center

-- 
Jani Nikula, Intel Open Source Graphics Center
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