Re: [PATCH 2/2] drm/i915/lspcon: Separate lspcon probe and lspcon init

["Nautiyal, Ankit K" <ankit.k.nautiyal@xxxxxxxxx>]

On 3/25/2024 8:48 PM, Jani Nikula wrote:
> On Fri, 22 Mar 2024, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> wrote:
> > Currently we probe for lspcon, inside lspcon init. Which does 2 things:
> > probe the lspcon and set the expected LS/PCON mode.
> >
> > If there is no lspcon connected, the probe expectedly fails and
> > results in error message. This inturn gets propogated to
> > lspcon init and we get again error message for lspcon init
> > failure.
> >
> > Separate the probe function and avoid displaying error if probe fails.
> > If probe succeeds, only then start lspcon init and set the expected
> > LS/PCON mode as first step.
> >
> > While at it move the drm_err message in lspcon init, instead of the
> > caller.
> >
> > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/display/intel_dp.c     |  3 +++
> >   drivers/gpu/drm/i915/display/intel_lspcon.c | 27 +++++++++++----------
> >   drivers/gpu/drm/i915/display/intel_lspcon.h |  1 +
> >   3 files changed, 18 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 94fa34f77cf0..ea8d3e70127e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -5882,6 +5882,9 @@ intel_dp_connector_register(struct drm_connector *connector)
> >   	 * ToDo: Clean this up to handle lspcon init and resume more
> >   	 * efficiently and streamlined.
> >   	 */
> > +	if (!lspcon_probe(lspcon))
> > +		return ret;
> > +
> >   	if (lspcon_init(dig_port)) {
> >   		lspcon_detect_hdr_capability(lspcon);
> >   		if (lspcon->hdr_supported)
> > diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c
> > index 62159d3ead56..570fde848d00 100644
> > --- a/drivers/gpu/drm/i915/display/intel_lspcon.c
> > +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
> > @@ -266,7 +266,7 @@ static bool lspcon_set_expected_mode(struct intel_lspcon *lspcon)
> >   	return true;
> >   }
> >   
> > -static bool lspcon_probe(struct intel_lspcon *lspcon)
> > +bool lspcon_probe(struct intel_lspcon *lspcon)
> >   {
> >   	int retry;
> >   	enum drm_dp_dual_mode_type adaptor_type;
> > @@ -676,30 +676,31 @@ bool lspcon_init(struct intel_digital_port *dig_port)
> >   	lspcon->active = false;
> >   	lspcon->mode = DRM_LSPCON_MODE_INVALID;
> >   
> > -	if (!lspcon_probe(lspcon)) {
> > -		drm_err(&i915->drm, "Failed to probe lspcon\n");
> > -		return false;
> > -	}
> > -
> >   	if (!lspcon_set_expected_mode(lspcon)) {
> >   		drm_err(&i915->drm, "LSPCON Set expected Mode failed\n");
> > -		return false;
> > +		goto lspcon_init_failed;
> >   	}
> >   
> >   	if (drm_dp_read_dpcd_caps(&intel_dp->aux, intel_dp->dpcd) != 0) {
> >   		drm_err(&i915->drm, "LSPCON DPCD read failed\n");
> > -		return false;
> > +		goto lspcon_init_failed;
> >   	}
> >   
> >   	if (!lspcon_detect_vendor(lspcon)) {
> >   		drm_err(&i915->drm, "LSPCON vendor detection failed\n");
> > -		return false;
> > +		goto lspcon_init_failed;
> >   	}
> >   
> >   	connector->ycbcr_420_allowed = true;
> >   	lspcon->active = true;
> >   	drm_dbg_kms(&i915->drm, "Success: LSPCON init\n");
> >   	return true;
> > +
> > +lspcon_init_failed:
> > +	drm_err(&i915->drm, "LSPCON init failed on port %c\n",
> > +		port_name(dig_port->base.port));
> I guess the idea is to reduce dmesg errors, but in this function the
> error messages are multiplied.

Earlier we used to get the drm_error for init failure, even if the 
LSPCON was not detected, which is printed as a debug print.

Now we'll get the dmesg errors only if we detect lspcon and lspcon init 
indeed fails.

Regards,

Ankit


> BR,
> Jani.
>
> > +
> > +	return false;
> >   }
> >   
> >   u32 intel_lspcon_infoframes_enabled(struct intel_encoder *encoder,
> > @@ -721,11 +722,11 @@ void lspcon_resume(struct intel_digital_port *dig_port)
> >   		return;
> >   
> >   	if (!lspcon->active) {
> > -		if (!lspcon_init(dig_port)) {
> > -			drm_err(&i915->drm, "LSPCON init failed on port %c\n",
> > -				port_name(dig_port->base.port));
> > +		if (!lspcon_probe(lspcon))
> > +			return;
> > +
> > +		if (!lspcon_init(dig_port))
> >   			return;
> > -		}
> >   	}
> >   
> >   	if (lspcon_wake_native_aux_ch(lspcon)) {
> > diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.h b/drivers/gpu/drm/i915/display/intel_lspcon.h
> > index e19e10492b05..b156cc6b3a23 100644
> > --- a/drivers/gpu/drm/i915/display/intel_lspcon.h
> > +++ b/drivers/gpu/drm/i915/display/intel_lspcon.h
> > @@ -16,6 +16,7 @@ struct intel_encoder;
> >   struct intel_lspcon;
> >   
> >   bool lspcon_init(struct intel_digital_port *dig_port);
> > +bool lspcon_probe(struct intel_lspcon *lspcon);
> >   void lspcon_detect_hdr_capability(struct intel_lspcon *lspcon);
> >   void lspcon_resume(struct intel_digital_port *dig_port);
> >   void lspcon_wait_pcon_mode(struct intel_lspcon *lspcon);