>-----Original Message----- >From: Navare, Manasi D >Sent: Tuesday, November 6, 2018 2:42 PM >To: Srivatsa, Anusha <anusha.sriva...@intel.com> >Cc: intel-...@lists.freedesktop.org; dri-devel@lists.freedesktop.org; Singh, >Gaurav K <gaurav.k.si...@intel.com>; Jani Nikula <jani.nik...@linux.intel.com>; >Ville Syrjala <ville.syrj...@linux.intel.com> >Subject: Re: [v6 3/4] i915/dp/fec: Configure the Forward Error Correction bits. > >On Mon, Nov 05, 2018 at 03:31:49PM -0800, 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. >> >> v5: >> - Move the code to the proper spot, according to spec.(Ville) >> - Use fec state as a check too. >> >> v6: Pass intel_encoder, instead of intel_dp. (Ville) >> >> Cc: dri-devel@lists.freedesktop.org >> Cc: Gaurav K Singh <gaurav.k.si...@intel.com> >> Cc: Jani Nikula <jani.nik...@linux.intel.com> >> Cc: Ville Syrjala <ville.syrj...@linux.intel.com> >> Cc: Manasi Navare <manasi.d.nav...@intel.com> >> Signed-off-by: Anusha Srivatsa <anusha.sriva...@intel.com> >> --- >> drivers/gpu/drm/i915/i915_reg.h | 2 ++ >> drivers/gpu/drm/i915/intel_ddi.c | 24 ++++++++++++++++++++++++ >> 2 files changed, 26 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/i915_reg.h >> b/drivers/gpu/drm/i915/i915_reg.h index 1a84e8f98e66..209b64d2f27a >> 100644 >> --- a/drivers/gpu/drm/i915/i915_reg.h >> +++ b/drivers/gpu/drm/i915/i915_reg.h >> @@ -9148,6 +9148,7 @@ 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) >> @@ -9166,6 +9167,7 @@ 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 53a9b31e66a2..fad7385dbd76 100644 >> --- a/drivers/gpu/drm/i915/intel_ddi.c >> +++ b/drivers/gpu/drm/i915/intel_ddi.c >> @@ -3065,6 +3065,28 @@ static void intel_dp_sink_set_fec_ready(struct >intel_dp *intel_dp, >> DRM_DEBUG_KMS("Failed to get FEC enabled in sink\n"); } >> >> +static void intel_ddi_enable_fec(struct intel_encoder *encoder, >> + const struct intel_crtc_state *crtc_state) { >> + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); >> + enum port port = encoder->port; >> + u32 val; >> + >> + /* FEC support exists for DP 1.4 only */ > >No need for this comment here now since all the platform and sink checks >already done while setting the the fec state. Agreed.
> >> + if (!crtc_state->fec_enable) >> + return; >> + >> + val = I915_READ(DP_TP_CTL(port)); >> + val |= DP_TP_CTL_FEC_ENABLE; >> + I915_WRITE(DP_TP_CTL(port), val); > >Do we need a POSTING_READ() here as well? It's used in case of disable fec in >DP_TP_CTL. >May be double check when we need it and when we don't. I don't think we need POSTING_READ, the spec says "wait for FEC_STATUS in DP_TP_CTL[28] is 1. That is why after the i915_WRITE above, I am using intel_Wait_for_register(). Anusha >Manasi > >> + >> + 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"); } >> + >> static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder, >> const struct intel_crtc_state *crtc_state, >> const struct drm_connector_state >*conn_state) @@ -3110,6 >> +3132,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder >*encoder, >> if (port != PORT_A || INTEL_GEN(dev_priv) >= 9) >> intel_dp_stop_link_train(intel_dp); >> >> + intel_ddi_enable_fec(encoder, crtc_state); >> + >> icl_enable_phy_clock_gating(dig_port); >> >> if (!is_mst) >> -- >> 2.19.1 >> _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel