On Tue, 27 May 2025, "Lee, Shawn C" <shawn.c....@intel.com> wrote:
> On Tue, 27 May 2025, Jani Nikula <jani.nik...@linux.intel.com> wrote:
>>On Tue, 27 May 2025, Lee Shawn C <shawn.c....@intel.com> wrote:
>>> A DSC setting has been available in VBT since version 251, which
>>> allows users to enable or disable the DSC feature based on their system
>>> design.
>>> With this in mind, DP driver should reference this setting and avoid
>>> enabling DSC if this value is not allowed.
>>>
>>> Cc: Shankar Uma <uma.shan...@intel.com>
>>> Cc: Jani Nikula <jani.nik...@linux.intel.com>
>>> Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
>>> Signed-off-by: Lee Shawn C <shawn.c....@intel.com>
>>> ---
>>> drivers/gpu/drm/i915/display/intel_bios.c | 8 ++++++++
>>> drivers/gpu/drm/i915/display/intel_bios.h | 1 +
>>> drivers/gpu/drm/i915/display/intel_dp.c | 12 +++++++++---
>>> drivers/gpu/drm/i915/display/intel_dp.h | 2 +-
>>> drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 +-
>>> 5 files changed, 20 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c
>>> b/drivers/gpu/drm/i915/display/intel_bios.c
>>> index ba7b8938b17c..f08dd54fe4d4 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_bios.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
>>> @@ -3548,6 +3548,14 @@ bool intel_bios_get_dsc_params(struct intel_encoder
>>> *encoder,
>>> return false;
>>> }
>>>
>>> +bool intel_bios_encoder_ext_display_dsc_disabled(const struct
>>> +intel_bios_encoder_data *devdata)
>>
>>Prefer positive instead of negative, and follow naming conventions.
>>
>>intel_bios_encoder_supports_dsc().
>>
>
> Sure! I will rename this function.
>
>>> +{
>>> + if (!devdata || devdata->display->vbt.version < 251)
>>> + return false;
>>> +
>>> + return devdata->child.disable_compression_for_ext_disp;
>>> +}
>>> +
>>> static const u8 adlp_aux_ch_map[] = {
>>> [AUX_CH_A] = DP_AUX_A,
>>> [AUX_CH_B] = DP_AUX_B,
>>> diff --git a/drivers/gpu/drm/i915/display/intel_bios.h
>>> b/drivers/gpu/drm/i915/display/intel_bios.h
>>> index 6cd7a011b8c4..901ba63e205d 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_bios.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
>>> @@ -258,6 +258,7 @@ bool
>>> intel_bios_encoder_supports_dp_dual_mode(const struct
>>> intel_bios_encoder_da bool intel_bios_encoder_is_lspcon(const struct
>>> intel_bios_encoder_data *devdata); bool
>>> intel_bios_encoder_lane_reversal(const struct intel_bios_encoder_data
>>> *devdata); bool intel_bios_encoder_hpd_invert(const struct
>>> intel_bios_encoder_data *devdata);
>>> +bool intel_bios_encoder_ext_display_dsc_disabled(const struct
>>> +intel_bios_encoder_data *devdata);
>>> enum port intel_bios_encoder_port(const struct
>>> intel_bios_encoder_data *devdata); enum aux_ch
>>> intel_bios_dp_aux_ch(const struct intel_bios_encoder_data *devdata);
>>> int intel_bios_dp_boost_level(const struct intel_bios_encoder_data
>>> *devdata); diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>>> b/drivers/gpu/drm/i915/display/intel_dp.c
>>> index 640c43bf62d4..eb1e6de0148a 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>>> @@ -1389,9 +1389,11 @@ int intel_dp_num_joined_pipes(struct intel_dp
>>> *intel_dp,
>>> return 1;
>>> }
>>>
>>> -bool intel_dp_has_dsc(const struct intel_connector *connector)
>>> +bool intel_dp_has_dsc(struct intel_dp *intel_dp,
>>
>>There's no need to pass that in.
>>
>
> intel_bios_encoder_supports_dsc() need intel_bios_encoder_data.
> That's why we pass intel_dp and use it to get ecoder data.
> Do you mean we can get encoder data from intel_connector?
You call intel_dp_has_dsc() from e.g. intel_dp_mode_valid() and that
figures out intel_dp from connector too. There's no need to pass
intel_dp around.
>
>>> + const struct intel_connector *connector)
>>> {
>>> struct intel_display *display = to_intel_display(connector);
>>> + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
>>>
>>> if (!HAS_DSC(display))
>>> return false;
>>> @@ -1403,6 +1405,10 @@ bool intel_dp_has_dsc(const struct intel_connector
>>> *connector)
>>> connector->panel.vbt.edp.dsc_disable)
>>> return false;
>>>
>>> + if (connector->base.connector_type == DRM_MODE_CONNECTOR_DisplayPort
>>> +&&
>>
>>It's just absolutely bonkers that the field is for external HDMI/DP, there's
>>a separate field for eDP DSC disable, and there's a separate field for DSI
>>DSC.
>>
>>Anyway, I am wondering if the output type check should be in
>>intel_bios_encoder_supports_dsc() instead.
>>
>>(intel_bios_encoder_supports_dp() && !intel_bios_encoder_supports_edp()) ||
>>intel_bios_encoder_supports_hdmi().
>>
>
> Sounds good! Let's move this checking into intel_bios_encoder_supports_dsc().
Hmm, one question though. Since the VBT field is so poorly documented,
should it apply to DP MST as well?!
BR,
Jani.
>
> Best regards,
> Shawn
>
>>BR,
>>Jani.
>>
>>> + intel_bios_encoder_ext_display_dsc_disabled(encoder->devdata))
>>> + return false;
>>> +
>>> if (!drm_dp_sink_supports_dsc(connector->dp.dsc_dpcd))
>>> return false;
>>>
>>> @@ -1463,7 +1469,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>>> mode_rate = intel_dp_link_required(target_clock,
>>>
>>> intel_dp_mode_min_output_bpp(connector, mode));
>>>
>>> - if (intel_dp_has_dsc(connector)) {
>>> + if (intel_dp_has_dsc(intel_dp, connector)) {
>>> enum intel_output_format sink_format, output_format;
>>> int pipe_bpp;
>>>
>>> @@ -1650,7 +1656,7 @@ bool intel_dp_supports_dsc(struct intel_dp *intel_dp,
>>> const struct intel_connector *connector,
>>> const struct intel_crtc_state *crtc_state) {
>>> - if (!intel_dp_has_dsc(connector))
>>> + if (!intel_dp_has_dsc(intel_dp, connector))
>>> return false;
>>>
>>> if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP) && diff --git
>>> a/drivers/gpu/drm/i915/display/intel_dp.h
>>> b/drivers/gpu/drm/i915/display/intel_dp.h
>>> index 742ae26ac4a9..309dad5b1b47 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_dp.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
>>> @@ -83,7 +83,7 @@ void intel_dp_audio_compute_config(struct
>>> intel_encoder *encoder, bool intel_dp_has_hdmi_sink(struct intel_dp
>>> *intel_dp); bool intel_dp_is_edp(struct intel_dp *intel_dp); bool
>>> intel_dp_is_uhbr(const struct intel_crtc_state *crtc_state); -bool
>>> intel_dp_has_dsc(const struct intel_connector *connector);
>>> +bool intel_dp_has_dsc(struct intel_dp *intel_dp, const struct
>>> +intel_connector *connector);
>>> int intel_dp_link_symbol_size(int rate); int
>>> intel_dp_link_symbol_clock(int rate); bool
>>> intel_dp_is_port_edp(struct intel_display *display, enum port port);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>> index c1fd6aceec2c..4f18059d9913 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>>> @@ -1508,7 +1508,7 @@ mst_connector_mode_valid_ctx(struct drm_connector
>>> *_connector,
>>> return 0;
>>> }
>>>
>>> - if (intel_dp_has_dsc(connector)) {
>>> + if (intel_dp_has_dsc(intel_dp, connector)) {
>>> /*
>>> * TBD pass the connector BPC,
>>> * for now U8_MAX so that max BPC on that platform would be
>>> picked
>>
>>--
>>Jani Nikula, Intel
>>
--
Jani Nikula, Intel
