On Mon, Jul 13, 2020 at 04:53:33PM -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
>
> v4:
> - using the HOBL vswing table until training fails completely (Ville)
>
> v5:
> - not reducing lane or link rate when link training fails with HOBL
> active
> - duplicated the HOBL voltage swing entry to match DP spec requirement
>
> BSpec: 49291
> BSpec: 49399
> Cc: Ville Syrjälä <[email protected]>
> Cc: Animesh Manna <[email protected]>
> Cc: Manasi Navare <[email protected]>
> Signed-off-by: José Roberto de Souza <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 42 +++++++++++++++++++
> .../drm/i915/display/intel_display_types.h | 2 +
> .../drm/i915/display/intel_dp_link_training.c | 19 ++++++---
> drivers/gpu/drm/i915/i915_reg.h | 2 +
> 4 files changed, 59 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 2c484b55bcdf..92ae036440fa 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -706,6 +706,29 @@ static const struct cnl_ddi_buf_trans
> tgl_combo_phy_ddi_translations_dp_hbr2[] =
> { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 900 900 0.0 */
> };
>
> +/*
> + * Cloned the HOBL entry to comply with the voltage and pre-emphasis entries
> + * that DisplayPort specification requires
> + */
> +static const struct cnl_ddi_buf_trans
> tgl_combo_phy_ddi_translations_edp_hbr2_hobl[] = {
> + /* VS pre-emp */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 0 0 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 0 1 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 0 2 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 0 3 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 1 0 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 1 1 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 1 2 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 2 0 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 2 1 */
> + { 0x6, 0x7F, 0x3F, 0x00, 0x00 }, /* 3 0 */
We could skip the last entry since that's still legal. Dunno which is
better though.
> +};
> +
> +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 +1073,16 @@ 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_failed && 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) {
> @@ -2392,6 +2425,15 @@ static void icl_ddi_combo_vswing_program(struct
> intel_encoder *encoder,
> level = n_entries - 1;
> }
>
> + if (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);
Still don't understand why we have these two booleans and this table
comparison. Why not just set the intel_dp->hobl=true intiailly
based on vbt, and clear it if and when link training fails?
> + intel_de_rmw(dev_priv, ICL_PORT_CL_DW10(phy), val,
> + intel_dp->hobl_active ? val : 0);
> + }
> +
> /* 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..5e6634b55e84 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_failed : 1, hobl_active : 1;
> };
>
> 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 a23ed7290843..f2c8b56be9ea 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -410,10 +410,17 @@ 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_get_link_train_fallback_values(intel_dp,
> - intel_dp->link_rate,
> - intel_dp->lane_count))
> - /* Schedule a Hotplug Uevent to userspace to start modeset */
> - schedule_work(&intel_connector->modeset_retry_work);
> - return;
> +
> + if (intel_dp->hobl_active) {
> + drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
> + "Link Training failed with HOBL active, not
> enabling it from now on");
> + intel_dp->hobl_failed = true;
> + } else if (intel_dp_get_link_train_fallback_values(intel_dp,
> + intel_dp->link_rate,
> +
> intel_dp->lane_count)) {
> + return;
> + }
> +
> + /* Schedule a Hotplug Uevent to userspace to start modeset */
> + schedule_work(&intel_connector->modeset_retry_work);
> }
> 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
--
Ville Syrjälä
Intel
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