Re: [Intel-gfx] [PATCH v3 6/9] drm/i915/mso: add splitter state readout for platforms that support it

Jani Nikula
2021-02-22T16:55:29Z

On Mon, 22 Feb 2021, "Shankar, Uma" <uma.shankar@intel.com> wrote:
>> -----Original Message-----
>> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Jani Nikula
>> Sent: Thursday, February 11, 2021 8:22 PM
>> To: intel-gfx@lists.freedesktop.org
>> Cc: Nikula, Jani <jani.nikula@intel.com>; Varide, Nischal <nischal.varide@intel.com>
>> Subject: [Intel-gfx] [PATCH v3 6/9] drm/i915/mso: add splitter state readout for
>> platforms that support it
>>
>> Add splitter configuration to crtc state, and read it where supported. Also add
>> splitter state dumping. The stream splitter will be required for eDP MSO.
>>
>> v3:
>> - Convert segment timings to full panel timings.
>> - Refer to splitter instead of mso in crtc state.
>> - Dump splitter state.
>>
>> v2: Add warning for mso being enabled on pipes other than A.
>>
>> Cc: Nischal Varide <nischal.varide@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>> drivers/gpu/drm/i915/display/intel_ddi.c | 37 +++++++++++++++++++
>> drivers/gpu/drm/i915/display/intel_display.c | 31 +++++++++++++++-
>> .../drm/i915/display/intel_display_types.h | 7 ++++
>> drivers/gpu/drm/i915/i915_drv.h | 2 +
>> 4 files changed, 75 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
>> b/drivers/gpu/drm/i915/display/intel_ddi.c
>> index 3c4003605f93..c9098297b6ac 100644
>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>> @@ -2132,6 +2132,41 @@ static void intel_ddi_power_up_lanes(struct
>> intel_encoder *encoder,
>> }
>> }
>>
>> +static void intel_ddi_mso_get_config(struct intel_encoder *encoder,
>> + struct intel_crtc_state *pipe_config) {
>> + struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
>> + struct drm_i915_private *i915 = to_i915(crtc->base.dev);
>> + enum pipe pipe = crtc->pipe;
>> + u32 dss1;
>> +
>> + if (!HAS_MSO(i915))
>> + return;
>> +
>> + dss1 = intel_de_read(i915, ICL_PIPE_DSS_CTL1(pipe));
>> +
>> + pipe_config->splitter.enable = dss1 & SPLITTER_ENABLE;
>> + if (!pipe_config->splitter.enable)
>> + return;
>> +
>> + /* Splitter enable is supported for pipe A only. */
>> + if (drm_WARN_ON(&i915->drm, pipe != PIPE_A)) {
>> + pipe_config->splitter.enable = false;
>> + return;
>> + }
>> +
>> + switch (dss1 & SPLITTER_CONFIGURATION_MASK) {
>> + case SPLITTER_CONFIGURATION_2_SEGMENT:
>> + pipe_config->splitter.link_count = 2;
>> + break;
>> + case SPLITTER_CONFIGURATION_4_SEGMENT:
>> + pipe_config->splitter.link_count = 4;
>> + break;
>
> Should we have a default case as well just for sanity along with a WARN, since it's very
> unlikely that it gets hit.

Ok.

>
>> + }
>> +
>> + pipe_config->splitter.pixel_overlap =
>> +REG_FIELD_GET(OVERLAP_PIXELS_MASK, dss1); }
>> +
>> static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
>> struct intel_encoder *encoder,
>> const struct intel_crtc_state *crtc_state, @@ -
>> 3322,6 +3357,8 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
>> intel_ddi_read_func_ctl(encoder, pipe_config);
>> }
>>
>> + intel_ddi_mso_get_config(encoder, pipe_config);
>> +
>> pipe_config->has_audio =
>> intel_ddi_is_audio_enabled(dev_priv, cpu_transcoder);
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
>> b/drivers/gpu/drm/i915/display/intel_display.c
>> index beed08c00b6c..fe9985bd5786 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -4856,8 +4856,30 @@ static void intel_crtc_readout_derived_state(struct
>> intel_crtc_state *crtc_state
>> pipe_mode->crtc_clock /= 2;
>> }
>>
>> - intel_mode_from_crtc_timings(pipe_mode, pipe_mode);
>> - intel_mode_from_crtc_timings(adjusted_mode, adjusted_mode);
>> + if (crtc_state->splitter.enable) {
>
> We can just add an else if case to if (crtc_state->bigjoiner) {
>
> if (crtc_state->bigjoiner) {
> ...
> } else if (crtc_state->splitter.enable) {
> ...
> }
>
>> + int n = crtc_state->splitter.link_count;
>> + int overlap = crtc_state->splitter.pixel_overlap;
>> +
>> + /*
>> + * eDP MSO uses segment timings from EDID for transcoder
>> + * timings, but full mode for everything else.
>> + *
>> + * h_full = (h_segment - pixel_overlap) * link_count
>> + */
>> + pipe_mode->crtc_hdisplay = (pipe_mode->crtc_hdisplay - overlap) *
>> n;
>> + pipe_mode->crtc_hblank_start = (pipe_mode->crtc_hblank_start -
>> overlap) * n;
>> + pipe_mode->crtc_hblank_end = (pipe_mode->crtc_hblank_end -
>> overlap) * n;
>> + pipe_mode->crtc_hsync_start = (pipe_mode->crtc_hsync_start -
>> overlap) * n;
>> + pipe_mode->crtc_hsync_end = (pipe_mode->crtc_hsync_end -
>> overlap) * n;
>> + pipe_mode->crtc_htotal = (pipe_mode->crtc_htotal - overlap) * n;
>> + pipe_mode->crtc_clock *= n;
>> +
>> + intel_mode_from_crtc_timings(pipe_mode, pipe_mode);
>> + intel_mode_from_crtc_timings(adjusted_mode, pipe_mode);
>
> Then we can keep above 2 out of the if conditions.

Note that the 2 lines in the if branches are *not* the same, and the
order matters!

I tried various alternatives, but to me this had the most clarity.

>
>> + } else {
>> + intel_mode_from_crtc_timings(pipe_mode, pipe_mode);
>> + intel_mode_from_crtc_timings(adjusted_mode, adjusted_mode);
>> + }
>>
>> intel_crtc_compute_pixel_rate(crtc_state);
>>
>> @@ -8259,6 +8281,11 @@ static void intel_dump_pipe_config(const struct
>> intel_crtc_state *pipe_config,
>> pipe_config->bigjoiner_slave ? "slave" :
>> pipe_config->bigjoiner ? "master" : "no");
>>
>> + drm_dbg_kms(&dev_priv->drm, "splitter: %s, link count %d, overlap %d\n",
>> + enableddisabled(pipe_config->splitter.enable),
>> + pipe_config->splitter.link_count,
>> + pipe_config->splitter.pixel_overlap);
>> +
>> if (pipe_config->has_pch_encoder)
>> intel_dump_m_n_config(pipe_config, "fdi",
>> pipe_config->fdi_lanes,
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index 71611b596c88..5564db512d22 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -1161,6 +1161,13 @@ struct intel_crtc_state {
>> u8 pipeline_full;
>> u16 flipline, vmin, vmax;
>> } vrr;
>> +
>> + /* Stream Splitter for eDP MSO */
>> + struct {
>> + bool enable;
>> + u8 link_count;
>> + u8 pixel_overlap;
>> + } splitter;
>
> For DSI which also has this in common along with MSO, may be we can take these link_count and
> pixel_overlap out of splitter which is more of a MSO feature. Thoughts ?

Ville suggested the same I think.

>
>> };
>>
>> enum intel_pipe_crc_source {
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 9f55b5e6d8c9..3d8be7b021d9 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -1709,6 +1709,8 @@ tgl_stepping_get(struct drm_i915_private *dev_priv)
>>
>> #define HAS_CSR(dev_priv) (INTEL_INFO(dev_priv)->display.has_csr)
>>
>> +#define HAS_MSO(i915) (INTEL_GEN(i915) >= 12)
>> +
>> #define HAS_RUNTIME_PM(dev_priv) (INTEL_INFO(dev_priv)->has_runtime_pm)
>> #define HAS_64BIT_RELOC(dev_priv) (INTEL_INFO(dev_priv)->has_64bit_reloc)
>>
>> --
>> 2.20.1
>>
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--
Jani Nikula, Intel Open Source Graphics Center