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

Shankar, Uma
2021-02-22T09:09:43Z

> -----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.

> + }
> +
> + 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.

> + } 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 ?

> };
>
> 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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