[Intel-gfx] [v2 5/6] i915/dp/fec: Configure the Forward Error Correction bits.
Manasi Navare
manasi.d.navare at intel.com
Fri Oct 19 20:29:05 UTC 2018
On Fri, Oct 19, 2018 at 10:58:29PM +0300, Ville Syrjälä wrote:
> On Fri, Oct 19, 2018 at 12:24:43PM -0700, Manasi Navare wrote:
> > On Fri, Oct 19, 2018 at 09:39:11PM +0300, Ville Syrjälä wrote:
> > > On Mon, Oct 15, 2018 at 02:50:36PM -0700, Anusha Srivatsa wrote:
> > > > If FEC is supported, the corresponding
> > > > DP_TP_CTL register bits have to be configured.
> > > >
> > > > The driver has to program the FEC_ENABLE in DP_TP_CTL[30] register
> > > > and wait till FEC_STATUS in DP_TP_CTL[28] is 1.
> > > > Also add the warn message to make sure that the control
> > > > register is already active while enabling FEC.
> > > >
> > > > v2:
> > > > - Change commit message. Configure fec state after
> > > > link training (Manasi, Gaurav)
> > > > - Remove redundent checks (Manasi)
> > > > - Remove the registers that get added automagically (Anusha)
> > > >
> > > > v3: s/intel_dp_set_fec_state()/intel_dp_enable_fec_state() (Gaurav)
> > > >
> > > > v4: rebased.
> > > >
> > > > Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
> > > > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > > > Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> > > > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > > > Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
> > > > ---
> > > > drivers/gpu/drm/i915/i915_reg.h | 2 ++
> > > > drivers/gpu/drm/i915/intel_ddi.c | 2 ++
> > > > drivers/gpu/drm/i915/intel_dp.c | 27 +++++++++++++++++++++++++++
> > > > drivers/gpu/drm/i915/intel_drv.h | 3 ++-
> > > > 4 files changed, 33 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > > index bcde78bc0027..c8d7fdcd7823 100644
> > > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > > @@ -9093,6 +9093,7 @@ enum skl_power_gate {
> > > > #define _DP_TP_CTL_B 0x64140
> > > > #define DP_TP_CTL(port) _MMIO_PORT(port, _DP_TP_CTL_A, _DP_TP_CTL_B)
> > > > #define DP_TP_CTL_ENABLE (1 << 31)
> > > > +#define DP_TP_CTL_FEC_ENABLE (1 << 30)
> > > > #define DP_TP_CTL_MODE_SST (0 << 27)
> > > > #define DP_TP_CTL_MODE_MST (1 << 27)
> > > > #define DP_TP_CTL_FORCE_ACT (1 << 25)
> > > > @@ -9111,6 +9112,7 @@ enum skl_power_gate {
> > > > #define _DP_TP_STATUS_A 0x64044
> > > > #define _DP_TP_STATUS_B 0x64144
> > > > #define DP_TP_STATUS(port) _MMIO_PORT(port, _DP_TP_STATUS_A, _DP_TP_STATUS_B)
> > > > +#define DP_TP_STATUS_FEC_ENABLE_LIVE (1 << 28)
> > > > #define DP_TP_STATUS_IDLE_DONE (1 << 25)
> > > > #define DP_TP_STATUS_ACT_SENT (1 << 24)
> > > > #define DP_TP_STATUS_MODE_STATUS_MST (1 << 23)
> > > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > > > index f531900165bf..67c013ea4d39 100644
> > > > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > > > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > > > @@ -2911,6 +2911,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> > > > DP_DECOMPRESSION_EN);
> > > > intel_dp_sink_set_fec_ready(intel_dp, crtc_state, DP_FEC_READY);
> > > > intel_dp_start_link_train(intel_dp);
> > > > + intel_dp_enable_fec_state(intel_dp, crtc_state);
> > >
> > > This doesn't look like the correct spot. According to the spec it
> > > should be after stop_link_train() (where we set DP_TP_CTL to
> > > to normal).
> > >
> >
> > Yes I see in the display port enabling sequence page of the spec, that it says enable FEC
> > after DP_TP_CTL is set to Normal. Also the FEC page says that this should be enabled only after ensuring that link training
> > completed. So according to that this call should happen after
> > intel_dp_stop_link_train().
> > So yes move this to after intel_dp_stop_link_training().
> >
> > > > +
> > > > if (port != PORT_A || INTEL_GEN(dev_priv) >= 9)
> > > > intel_dp_stop_link_train(intel_dp);
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > > index b4e8af3142a2..b9f85502d9ff 100644
> > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > @@ -3017,6 +3017,33 @@ void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
> > > > DRM_DEBUG_KMS("Failed to get FEC enabled in sink\n");
> > > > }
> > > >
> > > > +void intel_dp_enable_fec_state(struct intel_dp *intel_dp,
> > > > + const struct intel_crtc_state *crtc_state)
> > > > +{
> > > > + struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > > > + struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> > > > + enum port port = intel_dig_port->base.port;
> > > > + u32 val;
> > > > +
> > > > + /* FEC support exists for DP 1.4 only */
> > > > + if (intel_dp_is_edp(intel_dp))
> > > > + return;
> > > > +
> > > > + /* If Display Compression is not enabled, FEC need not be configured */
> > > > + if (!crtc_state->dsc_params.compression_enable)
> > > > + return;
> > > > +
> > > > + val = I915_READ(DP_TP_CTL(port));
> > > > + val |= DP_TP_CTL_FEC_ENABLE;
> > > > + I915_WRITE(DP_TP_CTL(port), val);
> > > > +
> > > > + if (intel_wait_for_register(dev_priv, DP_TP_STATUS(port),
> > > > + DP_TP_STATUS_FEC_ENABLE_LIVE,
> > > > + DP_TP_STATUS_FEC_ENABLE_LIVE,
> > > > + 1))
> > > > + DRM_ERROR("Timed out waiting for FEC Enable Status\n");
> > > > +}
> > >
> > > There is no reason to stick these into intel_dp.c when the
> > > only caller is in intel_ddi.c.
> > >
> >
> > So may be move the set_dsc_state function also from intel_dp.c to intel_ddi.c
> > Or does it make sense to move all these DSC related functions including fec to intel_dsc.c?
> >
> > > We also seem to be missing platform checks. FEC doesn't appear to
> > > be a thing prior to ICL. I guess the edp+compression_enable takes care
> > > of this, but I think I'd rather stick a new fec_enable bool into
> > > the crtc state. That way we get can add it to the state checker as well.
> > >
> >
> > fec_enable can be added to crtc_state->dsc_params may be?
>
> Isn't FEC something that can be used w/o DSC too?
>
Nope, FEC always goes hand in hand with DSC on external DP and that DSC on external DP
cannot be enabled without FEC.
Manasi
> >
> > Manasi
> >
> > > > +
> > > > /* If the sink supports it, try to set the power state appropriately */
> > > > void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
> > > > {
> > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > > > index fbc9fa06e8be..e51d612a9f42 100644
> > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > @@ -1532,7 +1532,6 @@ intel_encoder_current_mode(struct intel_encoder *encoder);
> > > > bool intel_port_is_tc(struct drm_i915_private *dev_priv, enum port port);
> > > > enum tc_port intel_port_to_tc(struct drm_i915_private *dev_priv,
> > > > enum port port);
> > > > -
> > > > enum pipe intel_get_pipe_from_connector(struct intel_connector *connector);
> > > > int intel_get_pipe_from_crtc_id_ioctl(struct drm_device *dev, void *data,
> > > > struct drm_file *file_priv);
> > > > @@ -1712,6 +1711,8 @@ void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
> > > > void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
> > > > const struct intel_crtc_state *crtc_state,
> > > > int state);
> > > > +void intel_dp_enable_fec_state(struct intel_dp *intel_dp,
> > > > + const struct intel_crtc_state *crtc_state);
> > > > void intel_dp_encoder_reset(struct drm_encoder *encoder);
> > > > void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
> > > > void intel_dp_encoder_destroy(struct drm_encoder *encoder);
> > > > --
> > > > 2.17.1
> > >
> > > --
> > > Ville Syrjälä
> > > Intel
>
> --
> Ville Syrjälä
> Intel
More information about the Intel-gfx
mailing list