[Intel-gfx] [PATCH v4 4/5] drm/i915/display: Implement HOBL
Souza, Jose
jose.souza at intel.com
Thu Jul 9 19:40:35 UTC 2020
On Thu, 2020-07-09 at 17:24 +0300, Ville Syrjälä wrote:
> On Wed, Jul 08, 2020 at 01:55:11PM -0700, José Roberto de Souza wrote:
> > Hours Of Battery Life is a new GEN12+ power-saving feature that allows
> > supported motherboards to use a special voltage swing table for eDP
> > panels that uses less power.
> >
> > So here if supported by HW, OEM will set it in VBT and i915 will try
> > to train link with HOBL vswing table if link training fails it fall
> > back to the original table.
> >
> > intel_ddi_dp_preemph_max() was optimized to only check the HOBL flag
> > instead of do something like is done in intel_ddi_dp_voltage_max()
> > because it is only called after the first entry of the voltage swing
> > table was loaded so the HOBL flag is valid at that point.
> >
> > v3:
> > - removed a few parameters of icl_ddi_combo_vswing_program() that
> > can be taken from encoder(TODO)
> >
> > v4:
> > - using the HOBL vswing table until training fails completely (Ville)
> >
> > BSpec: 49291
> > BSpec: 49399
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Animesh Manna <animesh.manna at intel.com>
> > Cc: Manasi Navare <manasi.d.navare at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_ddi.c | 37 ++++++++++++++++---
> > .../drm/i915/display/intel_display_types.h | 2 +
> > .../drm/i915/display/intel_dp_link_training.c | 5 +++
> > drivers/gpu/drm/i915/i915_reg.h | 2 +
> > 4 files changed, 41 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index 2c484b55bcdf..bf86c588f726 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -706,6 +706,15 @@ static const struct cnl_ddi_buf_trans tgl_combo_phy_ddi_translations_dp_hbr2[] =
> > { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 900 900 0.0 */
> > };
> >
> > +static const struct cnl_ddi_buf_trans tgl_combo_phy_ddi_translations_edp_hbr2_hobl[] = {
> > + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }
> > +};
> > +
> > +static bool is_hobl_buf_trans(const struct cnl_ddi_buf_trans *table)
> > +{
> > + return table == tgl_combo_phy_ddi_translations_edp_hbr2_hobl;
> > +}
> > +
> > static const struct ddi_buf_trans *
> > bdw_get_buf_trans_edp(struct intel_encoder *encoder, int *n_entries)
> > {
> > @@ -1050,6 +1059,16 @@ static const struct cnl_ddi_buf_trans *
> > tgl_get_combo_buf_trans(struct intel_encoder *encoder, int type, int rate,
> > int *n_entries)
> > {
> > + if (type == INTEL_OUTPUT_EDP && dev_priv->vbt.edp.hobl) {
> > + struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > +
> > + if (!intel_dp->hobl_disabled && rate <= 540000) {
> > + /* Same table applies to TGL, RKL and DG1 */
> > + *n_entries = ARRAY_SIZE(tgl_combo_phy_ddi_translations_edp_hbr2_hobl);
> > + return tgl_combo_phy_ddi_translations_edp_hbr2_hobl;
> > + }
> > + }
> > +
> > if (type == INTEL_OUTPUT_HDMI || type == INTEL_OUTPUT_EDP) {
> > return icl_get_combo_buf_trans(encoder, type, rate, n_entries);
> > } else if (rate > 270000) {
> > @@ -2223,13 +2242,12 @@ static u8 intel_ddi_dp_voltage_max(struct intel_dp *intel_dp)
> > DP_TRAIN_VOLTAGE_SWING_MASK;
> > }
> >
> > -/*
> > - * We assume that the full set of pre-emphasis values can be
> > - * used on all DDI platforms. Should that change we need to
> > - * rethink this code.
> > - */
> > static u8 intel_ddi_dp_preemph_max(struct intel_dp *intel_dp)
> > {
> > + /* HOBL voltage swing table only have one entry */
> > + if (intel_dp->hobl_active)
> > + return DP_TRAIN_PRE_EMPH_LEVEL_0;
>
> That's illegal. We need to claim support for at least all
> vswing/pre-emphasis levels 0-2. 3 is optional. Though there is
> some confusion around this in the eDP spec where it kinda seems suggest
> that even some of the level 2 things are optional. But it's so unclear
> I would defer to just trusting what the DP spec says.
Okay so in this case I should add more entries to tgl_combo_phy_ddi_translations_edp_hbr2_hobl with the same values to match the minimum required by
DP spec?
>
> /me goes to write the patch with the WARNs...
Will take a look.
>
>
> > +
> > return DP_TRAIN_PRE_EMPH_LEVEL_3;
> > }
> >
> > @@ -2392,6 +2410,15 @@ static void icl_ddi_combo_vswing_program(struct intel_encoder *encoder,
> > level = n_entries - 1;
> > }
> >
> > + if (INTEL_GEN(dev_priv) >= 12 && type == INTEL_OUTPUT_EDP) {
> > + struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > +
> > + val = EDP4K2K_MODE_OVRD_EN | EDP4K2K_MODE_OVRD_OPTIMIZED;
> > + intel_dp->hobl_active = is_hobl_buf_trans(ddi_translations);
> > + intel_de_rmw(dev_priv, ICL_PORT_CL_DW10(phy), val,
> > + intel_dp->hobl_active ? val : 0);
> > + }
>
> I'd still suggest writing that unconditionally.
Okay
>
> > +
> > /* Set PORT_TX_DW5 */
> > val = intel_de_read(dev_priv, ICL_PORT_TX_DW5_LN0(phy));
> > val &= ~(SCALING_MODE_SEL_MASK | RTERM_SELECT_MASK |
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index e8f809161c75..fd4f0e4d0be7 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1375,6 +1375,8 @@ struct intel_dp {
> >
> > /* Display stream compression testing */
> > bool force_dsc_en;
> > +
> > + u8 hobl_disabled : 1, hobl_active : 1, hobl_not_used : 6;
>
> Why did we go from a simple boolean to this complicated thing?
Will try to remove one.
>
> > };
> >
> > enum lspcon_vendor {
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > index 2493142a70e9..925822fd386d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > @@ -401,6 +401,11 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
> > intel_connector->base.base.id,
> > intel_connector->base.name,
> > intel_dp->link_rate, intel_dp->lane_count);
> > + if (intel_dp->hobl_active) {
> > + drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
> > + "Link Training failed with HOBL active, not enabling it for now on");
> > + intel_dp->hobl_disabled = true;
>
> I don't think we should do the link rate/lanes reduction in
> this case. Ie. we should just mark hobl as no good and retry
> the link training with the same link param limits.
Okay
>
> > + }
> > if (!intel_dp_get_link_train_fallback_values(intel_dp,
> > intel_dp->link_rate,
> > intel_dp->lane_count))
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 86a23ced051b..ea16931c0fa4 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -1898,6 +1898,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> > #define PWR_DOWN_LN_3_1_0 (0xb << 4)
> > #define PWR_DOWN_LN_MASK (0xf << 4)
> > #define PWR_DOWN_LN_SHIFT 4
> > +#define EDP4K2K_MODE_OVRD_EN (1 << 3)
> > +#define EDP4K2K_MODE_OVRD_OPTIMIZED (1 << 2)
> >
> > #define ICL_PORT_CL_DW12(phy) _MMIO(_ICL_PORT_CL_DW(12, phy))
> > #define ICL_LANE_ENABLE_AUX (1 << 0)
> > --
> > 2.27.0
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