Re: [Intel-gfx] [PATCH 07/16] drm/i915: Stop using group access when progrmming icl combo phy TX

Souza, Jose
2021-10-29T21:53:11Z

On Wed, 2021-10-06 at 23:49 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Program each TX lane individually so that we can start to use per-lane
> drive settings.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 28 ++++++++++++++----------
> 1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index d06c76694a08..aa789cabc55b 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -1068,14 +1068,16 @@ static void icl_ddi_combo_vswing_program(struct intel_encoder *encoder,
> intel_de_write(dev_priv, ICL_PORT_TX_DW5_GRP(phy), val);
>
> /* Program PORT_TX_DW2 */
> - val = intel_de_read(dev_priv, ICL_PORT_TX_DW2_LN(0, phy));
> - val &= ~(SWING_SEL_LOWER_MASK | SWING_SEL_UPPER_MASK |
> - RCOMP_SCALAR_MASK);
> - val |= SWING_SEL_UPPER(trans->entries[level].icl.dw2_swing_sel);
> - val |= SWING_SEL_LOWER(trans->entries[level].icl.dw2_swing_sel);
> - /* Program Rcomp scalar for every table entry */
> - val |= RCOMP_SCALAR(0x98);
> - intel_de_write(dev_priv, ICL_PORT_TX_DW2_GRP(phy), val);
> + for (ln = 0; ln < 4; ln++) {
> + val = intel_de_read(dev_priv, ICL_PORT_TX_DW2_LN(ln, phy));
> + val &= ~(SWING_SEL_LOWER_MASK | SWING_SEL_UPPER_MASK |
> + RCOMP_SCALAR_MASK);
> + val |= SWING_SEL_UPPER(trans->entries[level].icl.dw2_swing_sel);
> + val |= SWING_SEL_LOWER(trans->entries[level].icl.dw2_swing_sel);
> + /* Program Rcomp scalar for every table entry */
> + val |= RCOMP_SCALAR(0x98);
> + intel_de_write(dev_priv, ICL_PORT_TX_DW2_LN(ln, phy), val);
> + }
>
> /* Program PORT_TX_DW4 */
> /* We cannot write to GRP. It would overwrite individual loadgen. */
> @@ -1090,10 +1092,12 @@ static void icl_ddi_combo_vswing_program(struct intel_encoder *encoder,
> }
>
> /* Program PORT_TX_DW7 */
> - val = intel_de_read(dev_priv, ICL_PORT_TX_DW7_LN(0, phy));
> - val &= ~N_SCALAR_MASK;
> - val |= N_SCALAR(trans->entries[level].icl.dw7_n_scalar);
> - intel_de_write(dev_priv, ICL_PORT_TX_DW7_GRP(phy), val);
> + for (ln = 0; ln < 4; ln++) {
> + val = intel_de_read(dev_priv, ICL_PORT_TX_DW7_LN(ln, phy));
> + val &= ~N_SCALAR_MASK;
> + val |= N_SCALAR(trans->entries[level].icl.dw7_n_scalar);
> + intel_de_write(dev_priv, ICL_PORT_TX_DW7_LN(ln, phy), val);
> + }
> }

Missing DSI conversion but from what I understood this conversion from group to lane is to support DP 2.0 so we can keep the group write for DSI.

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

>
> static void icl_combo_phy_set_signal_levels(struct intel_encoder *encoder,