[PATCH v6 13/28] drm/i915/dp: Compute DSC pipe config in atomic check
Ville Syrjälä
ville.syrjala at linux.intel.com
Tue Oct 30 11:41:56 UTC 2018
On Mon, Oct 29, 2018 at 03:12:51PM -0700, Manasi Navare wrote:
> On Mon, Oct 29, 2018 at 10:30:39PM +0200, Ville Syrjälä wrote:
> > On Wed, Oct 24, 2018 at 03:28:25PM -0700, Manasi Navare wrote:
> > > DSC params like the enable, compressed bpp, slice count and
> > > dsc_split are added to the intel_crtc_state. These parameters
> > > are set based on the requested mode and available link parameters
> > > during the pipe configuration in atomic check phase.
> > > These values are then later used to populate the remaining DSC
> > > and RC parameters before enbaling DSC in atomic commit.
> > >
> > > v9:
> > > * Rebase on top of drm-tip that now uses fast_narrow config
> > > for edp (Manasi)
> > > v8:
> > > * Check for DSC bpc not 0 (manasi)
> > >
> > > v7:
> > > * Fix indentation in compute_m_n (Manasi)
> > >
> > > v6 (From Gaurav):
> > > * Remove function call of intel_dp_compute_dsc_params() and
> > > invoke intel_dp_compute_dsc_params() in the patch where
> > > it is defined to fix compilation warning (Gaurav)
> > >
> > > v5:
> > > Add drm_dsc_cfg in intel_crtc_state (Manasi)
> > >
> > > v4:
> > > * Rebase on refactoring of intel_dp_compute_config on tip (Manasi)
> > > * Add a comment why we need to check PSR while enabling DSC (Gaurav)
> > >
> > > v3:
> > > * Check PPR > max_cdclock to use 2 VDSC instances (Ville)
> > >
> > > v2:
> > > * Add if-else for eDP/DP (Gaurav)
> > >
> > > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > > Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> > > Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> > > Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
> > > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > > Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
> > > Acked-by: Jani Nikula <jani.nikula at linux.intel.com>
> > > ---
> > > drivers/gpu/drm/i915/intel_display.c | 20 +++-
> > > drivers/gpu/drm/i915/intel_display.h | 3 +-
> > > drivers/gpu/drm/i915/intel_dp.c | 170 ++++++++++++++++++++++-----
> > > drivers/gpu/drm/i915/intel_dp_mst.c | 2 +-
> > > 4 files changed, 155 insertions(+), 40 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > > index fe045abb6472..18737bd82b68 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > @@ -6434,7 +6434,7 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
> > >
> > > pipe_config->fdi_lanes = lane;
> > >
> > > - intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock,
> > > + intel_link_compute_m_n(pipe_config->pipe_bpp, 0, lane, fdi_dotclock,
> > > link_bw, &pipe_config->fdi_m_n, false);
> > >
> > > ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config);
> > > @@ -6671,17 +6671,25 @@ static void compute_m_n(unsigned int m, unsigned int n,
> > > }
> > >
> > > void
> > > -intel_link_compute_m_n(int bits_per_pixel, int nlanes,
> > > +intel_link_compute_m_n(int bits_per_pixel, uint16_t compressed_bpp,
> > > + int nlanes,
> > > int pixel_clock, int link_clock,
> > > struct intel_link_m_n *m_n,
> > > bool constant_n)
> > > {
> > > m_n->tu = 64;
> > >
> > > - compute_m_n(bits_per_pixel * pixel_clock,
> > > - link_clock * nlanes * 8,
> > > - &m_n->gmch_m, &m_n->gmch_n,
> > > - constant_n);
> > > + /* For DSC, Data M/N calculation uses compressed BPP */
> > > + if (compressed_bpp)
> > > + compute_m_n(compressed_bpp * pixel_clock,
> > > + link_clock * nlanes * 8,
> > > + &m_n->gmch_m, &m_n->gmch_n,
> > > + constant_n);
> > > + else
> > > + compute_m_n(bits_per_pixel * pixel_clock,
> > > + link_clock * nlanes * 8,
> > > + &m_n->gmch_m, &m_n->gmch_n,
> > > + constant_n);
> > >
> > > compute_m_n(pixel_clock, link_clock,
> > > &m_n->link_m, &m_n->link_n,
> > > diff --git a/drivers/gpu/drm/i915/intel_display.h b/drivers/gpu/drm/i915/intel_display.h
> > > index 5d50decbcbb5..b0b23e1e9392 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.h
> > > +++ b/drivers/gpu/drm/i915/intel_display.h
> > > @@ -407,7 +407,8 @@ struct intel_link_m_n {
> > > (__i)++) \
> > > for_each_if(plane)
> > >
> > > -void intel_link_compute_m_n(int bpp, int nlanes,
> > > +void intel_link_compute_m_n(int bpp, uint16_t compressed_bpp,
> > > + int nlanes,
> > > int pixel_clock, int link_clock,
> > > struct intel_link_m_n *m_n,
> > > bool constant_n);
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index 6f66a38ba0b2..a88f9371dd32 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -47,6 +47,8 @@
> > >
> > > /* DP DSC small joiner has 2 FIFOs each of 640 x 6 bytes */
> > > #define DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER 61440
> > > +#define DP_DSC_MIN_SUPPORTED_BPC 8
> > > +#define DP_DSC_MAX_SUPPORTED_BPC 10
> > >
> > > /* DP DSC throughput values used for slice count calculations KPixels/s */
> > > #define DP_DSC_PEAK_PIXEL_RATE 2720000
> > > @@ -1924,6 +1926,16 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
> > > }
> > > }
> > >
> > > + /* If DSC is supported, use the max value reported by panel */
> > > + if (INTEL_GEN(dev_priv) >= 10 &&
> > > + drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)) {
> > > + bpc = min_t(u8,
> > > + drm_dp_dsc_sink_max_color_depth(intel_dp->dsc_dpcd),
> > > + DP_DSC_MAX_SUPPORTED_BPC);
> > > + if (bpc)
> > > + bpp = 3 * bpc;
> >
> > This seems like it should be 'bpp = min(bpp, 3*bpc)'.
> > Otherwise we may bump the bpp above a limit we already established earlier.
> >
>
> Yes will make this change.
>
> > > + }
> > > +
> > > return bpp;
> > > }
> > >
> > > @@ -1984,14 +1996,11 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> > > link_clock = intel_dp->common_rates[clock];
> > > link_avail = intel_dp_max_data_rate(link_clock,
> > > lane_count);
> > > -
> > > - if (mode_rate <= link_avail) {
> > > - pipe_config->lane_count = lane_count;
> > > - pipe_config->pipe_bpp = bpp;
> > > - pipe_config->port_clock = link_clock;
> > > -
> > > + pipe_config->lane_count = lane_count;
> > > + pipe_config->pipe_bpp = bpp;
> > > + pipe_config->port_clock = link_clock;
> > > + if (mode_rate <= link_avail)
> > > return true;
> >
> > Why do we need to assign these if we don't accept the configuration?
>
> We need to assign them because in case of failure, we use them to then configure DSC parameters
> in intel_dp_dsc_compute_config().
What you are doing is now is effectively:
pipe_config->lane_count = max_lanes;
pipe_config->pipe_bpp = min_bpp;
pipe_config->port_clock = max_clock;
So might as well do that explicitly in dsc_compute_config() then.
Not sure that makes sense though. Maybe we DSC we can make due
with a slower/narrower link? So we might want to iterate the
possible configurations again with dsc.
> Previously we were just returning a failure if this failed and so we need not ssign them. But now
> in case this fails, we try the DSC compute config.
>
> >
> > > - }
> > > }
> > > }
> > > }
> > > @@ -2020,14 +2029,11 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> > > link_clock = intel_dp->common_rates[clock];
> > > link_avail = intel_dp_max_data_rate(link_clock,
> > > lane_count);
> > > -
> > > - if (mode_rate <= link_avail) {
> > > - pipe_config->lane_count = lane_count;
> > > - pipe_config->pipe_bpp = bpp;
> > > - pipe_config->port_clock = link_clock;
> > > -
> > > + pipe_config->lane_count = lane_count;
> > > + pipe_config->pipe_bpp = bpp;
> > > + pipe_config->port_clock = link_clock;
> > > + if (mode_rate <= link_avail)
> > > return true;
> > > - }
> > > }
> > > }
> > > }
> > > @@ -2035,14 +2041,88 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> > > return false;
> > > }
> > >
> > > +static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > > + struct intel_crtc_state *pipe_config,
> > > + struct link_config_limits *limits)
> > > +{
> > > + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> > > + struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> > > + struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> > > + enum pipe pipe = to_intel_crtc(pipe_config->base.crtc)->pipe;
> > > + u16 dsc_max_output_bpp = 0;
> > > + u8 dsc_dp_slice_count = 0;
> > > +
> > > + if (INTEL_GEN(dev_priv) < 10 ||
> > > + !drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd))
> > > + return false;
> > > +
> > > + /* DP DSC only supported on Pipe B and C */
> > > + if (pipe == PIPE_A && !intel_dp_is_edp(intel_dp))
> > > + return false;
> >
> > Do we mean 'transcoder == EDP || transcoder == B || transcoder == C' ?
> > Or maybe 'transcoder != A' for short. I guess this will need to adjusted
> > for the next platform anyway so making the assumption that transcoder A
> > is the only one that can't do DSC is fine.
>
> Yes the mode I am trying to reject is in case of a NUC, where there is no edp, the first
> DP connection will use Pipe A and transcoder A which does not support DSC. So reject it.
> So yea I guess I could just check for transcoder == A , then reject.
>
> >
> > This whole thing seems like a good helper function.
> > intel_dp_source_supports_dsc() or something like that. And then we
> > could have intel_dp_supports_dsc() which just calls that +
> > drm_dp_sink_supports_dsc().
> >
> > intel_dp_compute_bpp() should use this at least, and probably a few
> > other places as well.
> >
> > > +
> > > + /* DSC not supported for DSC sink BPC < 8 */
> > > + if (limits->max_bpp < 3 * DP_DSC_MIN_SUPPORTED_BPC) {
> > > + DRM_DEBUG_KMS("No DSC support for less than 8bpc\n");
> > > + return false;
> > > + }
> > > +
> > > + if (intel_dp_is_edp(intel_dp)) {
> > > + pipe_config->dsc_params.compressed_bpp =
> > > + drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd) >> 4;
> > > + pipe_config->dsc_params.slice_count =
> > > + drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
> > > + true);
> > > + } else {
> > > + dsc_max_output_bpp =
> > > + intel_dp_dsc_get_output_bpp(pipe_config->port_clock,
> > > + pipe_config->lane_count,
> > > + adjusted_mode->crtc_clock,
> > > + adjusted_mode->crtc_hdisplay);
> > > + dsc_dp_slice_count =
> > > + intel_dp_dsc_get_slice_count(intel_dp,
> > > + adjusted_mode->crtc_clock,
> > > + adjusted_mode->crtc_hdisplay);
> > > + if (!(dsc_max_output_bpp && dsc_dp_slice_count)) {
> > > + DRM_DEBUG_KMS("Compressed BPP/Slice Count not supported\n");
> > > + return false;
> > > + }
> > > + pipe_config->dsc_params.compressed_bpp = dsc_max_output_bpp >> 4;
> > > + pipe_config->dsc_params.slice_count = dsc_dp_slice_count;
> > > + }
> > > + /*
> > > + * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate
> > > + * is greater than the maximum Cdclock and if slice count is even
> > > + * then we need to use 2 VDSC instances.
> > > + */
> > > + pipe_config->dsc_params.dsc_split = false;
> > > + if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) {
> > > + if (pipe_config->dsc_params.slice_count > 1) {
> > > + pipe_config->dsc_params.dsc_split = true;
> > > + } else {
> > > + DRM_DEBUG_KMS("Cannot split stream to use 2 VDSC instances\n");
> > > + return false;
> > > + }
> > > + }
> > > + pipe_config->dsc_params.compression_enable = true;
> > > + DRM_DEBUG_KMS("DP DSC computed with Input Bpp = %d "
> > > + "Compressed Bpp = %d Slice Count = %d\n",
> > > + pipe_config->pipe_bpp,
> > > + pipe_config->dsc_params.compressed_bpp,
> > > + pipe_config->dsc_params.slice_count);
> > > +
> > > + return true;
> > > +}
> > > +
> > > static bool
> > > intel_dp_compute_link_config(struct intel_encoder *encoder,
> > > struct intel_crtc_state *pipe_config)
> > > {
> > > + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > > struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> > > struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> > > struct link_config_limits limits;
> > > int common_len;
> > > + bool ret = false;
> > >
> > > common_len = intel_dp_common_len_rate_limit(intel_dp,
> > > intel_dp->max_link_rate);
> > > @@ -2056,7 +2136,9 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> > > limits.min_lane_count = 1;
> > > limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> > >
> > > - limits.min_bpp = 6 * 3;
> > > + limits.min_bpp = (INTEL_GEN(dev_priv) >= 10 &&
> > > + drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)) ?
> > > + DP_DSC_MIN_SUPPORTED_BPC * 3 : 6 * 3;
> > > limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> >
> > Hmm. This now assumes that we will in fact use DSC. I guess we can only
> > make that assumption when we've determined that DSC is supported and the
> > max_bpp also allows DSC.
>
> But the intel_dp_compute_bpp does check for supports_dsc so that
> should be fine. But for min_bpp yes I could use the below logic.
min_bpp is what I'm talking about here. We can't set it assuming DSC
will be used if the max_bpp is already below the DSC minimum.
> And may be move that to a helper?
Is there some other use for it? I'd rather keep this "populate the
limits" thing in one spot.
>
> Manasi
>
>
> >
> > So something like:
> >
> > max_bpp = intel_dp_compute_bpp();
> > if (supports_dsc() && max_bpp >= DP_DSC_MIN_SUPPORTED_BPC*3)
> > min_bpp = DP_DSC_MIN_SUPPORTED_BPC * 3;
> > else
> > min_bpp = 6 * 3
> >
> > >
> > > if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> > > @@ -2081,7 +2163,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> > > intel_dp->common_rates[limits.max_clock],
> > > limits.max_bpp, adjusted_mode->crtc_clock);
> > >
> > > - if (intel_dp_is_edp(intel_dp)) {
> > > + if (intel_dp_is_edp(intel_dp))
> > > /*
> > > * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> > > * section A.1: "It is recommended that the minimum number of
> > > @@ -2091,26 +2173,48 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> > > * Note that we use the max clock and lane count for eDP 1.3 and
> > > * earlier, and fast vs. wide is irrelevant.
> > > */
> > > - if (!intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> > > - &limits))
> > > - return false;
> > > - } else {
> > > + ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> > > + &limits);
> > > + else
> > > /* Optimize for slow and wide. */
> > > - if (!intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> > > - &limits))
> > > + ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> > > + &limits);
> > > +
> > > + /* enable compression if the mode doesn't fit available BW */
> > > + if (!ret) {
> > > + DRM_DEBUG_KMS("DP required Link rate %i does not fit available %i\n",
> > > + intel_dp_link_required(adjusted_mode->crtc_clock,
> > > + pipe_config->pipe_bpp),
> > > + intel_dp_max_data_rate(pipe_config->port_clock,
> > > + pipe_config->lane_count));
> > > +
> > > + if (!intel_dp_dsc_compute_config(intel_dp, pipe_config,
> > > + &limits))
> > > return false;
> > > }
> > >
> > > - DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
> > > - pipe_config->lane_count, pipe_config->port_clock,
> > > - pipe_config->pipe_bpp);
> > > + if (pipe_config->dsc_params.compression_enable) {
> > > + DRM_DEBUG_KMS("DP lane count %d clock %d Input bpp %d Compressed bpp %d\n",
> > > + pipe_config->lane_count, pipe_config->port_clock,
> > > + pipe_config->pipe_bpp,
> > > + pipe_config->dsc_params.compressed_bpp);
> > >
> > > - DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> > > - intel_dp_link_required(adjusted_mode->crtc_clock,
> > > - pipe_config->pipe_bpp),
> > > - intel_dp_max_data_rate(pipe_config->port_clock,
> > > - pipe_config->lane_count));
> > > + DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> > > + intel_dp_link_required(adjusted_mode->crtc_clock,
> > > + pipe_config->dsc_params.compressed_bpp),
> > > + intel_dp_max_data_rate(pipe_config->port_clock,
> > > + pipe_config->lane_count));
> > > + } else {
> > > + DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
> > > + pipe_config->lane_count, pipe_config->port_clock,
> > > + pipe_config->pipe_bpp);
> > >
> > > + DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> > > + intel_dp_link_required(adjusted_mode->crtc_clock,
> > > + pipe_config->pipe_bpp),
> > > + intel_dp_max_data_rate(pipe_config->port_clock,
> > > + pipe_config->lane_count));
> > > + }
> > > return true;
> > > }
> > >
> > > @@ -2194,7 +2298,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> > > intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_LIMITED;
> > > }
> > >
> > > - intel_link_compute_m_n(pipe_config->pipe_bpp, pipe_config->lane_count,
> > > + intel_link_compute_m_n(pipe_config->pipe_bpp,
> > > + pipe_config->dsc_params.compressed_bpp,
> > > + pipe_config->lane_count,
> > > adjusted_mode->crtc_clock,
> > > pipe_config->port_clock,
> > > &pipe_config->dp_m_n,
> > > @@ -2203,7 +2309,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> > > if (intel_connector->panel.downclock_mode != NULL &&
> > > dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
> > > pipe_config->has_drrs = true;
> > > - intel_link_compute_m_n(pipe_config->pipe_bpp,
> > > + intel_link_compute_m_n(pipe_config->pipe_bpp, 0,
> > > pipe_config->lane_count,
> > > intel_connector->panel.downclock_mode->clock,
> > > pipe_config->port_clock,
> > > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> > > index 8b71d64ebd9d..e02caedd443c 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > > @@ -90,7 +90,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > > }
> > > }
> > >
> > > - intel_link_compute_m_n(bpp, lane_count,
> > > + intel_link_compute_m_n(bpp, 0, lane_count,
> > > adjusted_mode->crtc_clock,
> > > pipe_config->port_clock,
> > > &pipe_config->dp_m_n,
> > > --
> > > 2.18.0
> >
> > --
> > Ville Syrjälä
> > Intel
--
Ville Syrjälä
Intel
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