On Tue, 01 Oct 2024, Imre Deak <imre.deak@xxxxxxxxx> wrote:
> While updating the source OUI on the sink the driver should avoid
> writing the OUI if it's already up-to-date to prevent the sink from
> resetting itself in response to the update. On eDP - the only output
> type where the OUI was updated so far - the driver ensured this by
> comparing the current source OUI DPCD register values with the expected
> Intel OUI value, skipping the update in case of a match. On some non-eDP
> sinks - at least on Synaptics branch devices - this method doesn't work,
> since the source OUI DPCD registers read back as all 0, even after
> updating the registers.
>
> Handle the above kind of sinks by tracking when the OUI was updated and
> so should be valid, regardless of what the DPCD registers contain.
>
> This is required by the next patch updating the source OUI on non-eDP
> sink types as well.
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/g4x_dp.c | 1 +
> drivers/gpu/drm/i915/display/intel_ddi.c | 1 +
> .../drm/i915/display/intel_display_types.h | 1 +
> drivers/gpu/drm/i915/display/intel_dp.c | 25 ++++++++++++++-----
> drivers/gpu/drm/i915/display/intel_dp.h | 1 +
> 5 files changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
> index 440fb3002f286..596e926ef0894 100644
> --- a/drivers/gpu/drm/i915/display/g4x_dp.c
> +++ b/drivers/gpu/drm/i915/display/g4x_dp.c
> @@ -1251,6 +1251,7 @@ static void intel_dp_encoder_reset(struct drm_encoder *encoder)
> intel_dp->DP = intel_de_read(display, intel_dp->output_reg);
>
> intel_dp->reset_link_params = true;
> + intel_dp_invalidate_source_oui(intel_dp);
>
> if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> vlv_pps_pipe_reset(intel_dp);
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index fe1ded6707f90..465f245a53c48 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -4392,6 +4392,7 @@ static void intel_ddi_encoder_reset(struct drm_encoder *encoder)
> struct intel_digital_port *dig_port = enc_to_dig_port(to_intel_encoder(encoder));
>
> intel_dp->reset_link_params = true;
> + intel_dp_invalidate_source_oui(intel_dp);
>
> intel_pps_encoder_reset(intel_dp);
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 7ff97e5b83dd5..ad84ffa31c97f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1757,6 +1757,7 @@ struct intel_dp {
>
> /* When we last wrote the OUI for eDP */
> unsigned long last_oui_write;
> + bool oui_valid;
>
> bool colorimetry_support;
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index b7661529f1927..2d6ffbeae07a0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3335,31 +3335,43 @@ void intel_dp_sink_disable_decompression(struct intel_atomic_state *state,
> }
>
> static void
> -intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful)
> +intel_dp_init_source_oui(struct intel_dp *intel_dp)
> {
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> u8 oui[] = { 0x00, 0xaa, 0x01 };
> u8 buf[3] = {};
>
> + if (!intel_dp_is_edp(intel_dp))
> + return;
> +
> /*
> * During driver init, we want to be careful and avoid changing the source OUI if it's
> * already set to what we want, so as to avoid clearing any state by accident
> */
> - if (careful) {
> + if (!intel_dp->oui_valid) {
> if (drm_dp_dpcd_read(&intel_dp->aux, DP_SOURCE_OUI, buf, sizeof(buf)) < 0)
> drm_err(&i915->drm, "Failed to read source OUI\n");
>
> if (memcmp(oui, buf, sizeof(oui)) == 0) {
> /* Assume the OUI was written now. */
> intel_dp->last_oui_write = jiffies;
> - return;
> + intel_dp->oui_valid = true;
> }
> }
>
> + if (intel_dp->oui_valid)
> + return;
> +
> if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) < 0)
> drm_err(&i915->drm, "Failed to write source OUI\n");
>
> intel_dp->last_oui_write = jiffies;
> + intel_dp->oui_valid = true;
Looking at patches 1 and 2, I'm thinking we don't need two members for
this.
Just make intel_dp->last_oui_write == 0 mean "invalid".
BR,
Jani.
> +}
> +
> +void intel_dp_invalidate_source_oui(struct intel_dp *intel_dp)
> +{
> + intel_dp->oui_valid = false;
> }
>
> void intel_dp_wait_source_oui(struct intel_dp *intel_dp)
> @@ -3390,6 +3402,8 @@ void intel_dp_set_power(struct intel_dp *intel_dp, u8 mode)
> if (downstream_hpd_needs_d0(intel_dp))
> return;
>
> + intel_dp_invalidate_source_oui(intel_dp);
> +
> ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER, mode);
> } else {
> struct intel_lspcon *lspcon = dp_to_lspcon(intel_dp);
> @@ -3397,8 +3411,7 @@ void intel_dp_set_power(struct intel_dp *intel_dp, u8 mode)
> lspcon_resume(dp_to_dig_port(intel_dp));
>
> /* Write the source OUI as early as possible */
> - if (intel_dp_is_edp(intel_dp))
> - intel_edp_init_source_oui(intel_dp, false);
> + intel_dp_init_source_oui(intel_dp);
>
> /*
> * When turning on, we need to retry for 1ms to give the sink
> @@ -4115,7 +4128,7 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp, struct intel_connector *connector
> * If needed, program our source OUI so we can make various Intel-specific AUX services
> * available (such as HDR backlight controls)
> */
> - intel_edp_init_source_oui(intel_dp, true);
> + intel_dp_init_source_oui(intel_dp);
>
> return true;
> }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 3b869429e5756..0449d1d3f175d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -189,6 +189,7 @@ void intel_dp_check_frl_training(struct intel_dp *intel_dp);
> void intel_dp_pcon_dsc_configure(struct intel_dp *intel_dp,
> const struct intel_crtc_state *crtc_state);
>
> +void intel_dp_invalidate_source_oui(struct intel_dp *intel_dp);
> void intel_dp_wait_source_oui(struct intel_dp *intel_dp);
> int intel_dp_output_bpp(enum intel_output_format output_format, int bpp);
--
Jani Nikula, Intel
