From: Arun R Murthy Date: Wed, 22 Jan 2025 05:55:42 +0000 (+0530) Subject: drm/i915/dp: Guarantee a minimum HBlank time X-Git-Tag: v6.15-rc1~120^2~16^2~144 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a5ebe00c2ace15634c02e3c64f1b28253553495b;p=thirdparty%2Fkernel%2Flinux.git drm/i915/dp: Guarantee a minimum HBlank time Mandate a minimum Hblank symbol cycle count between BlankingStart and BlankingEnd in 8b/10b MST and 128b/132b mode. v2: Affine calculation/updation of min HBlank to dp_mst (Jani) v3: moved min_hblank from struct intel_dp to intel_crtc_state (Jani) v4: use max/min functions, change intel_xx *intel_xx to intel_xx *xx (Jani) Limit hblank to 511 and accommodate BS/BE in calculated value (Srikanth) v5: Some spelling corrections (Suraj) v6: Removed DP2.1 in comment as this is applicable for both DP2.1 and DP1.4 (Suraj) v7: crtc_state holds the logical values and the register value computation is moved to mst_enable() (Jani) v8: Limit max hblank to 0x10, disable min_hblank on mst_disable (Jani) Bspec: 74379 Signed-off-by: Arun R Murthy Reviewed-by: Suraj Kandpal Acked-by: Jani Nikula Signed-off-by: Suraj Kandpal Link: https://patchwork.freedesktop.org/patch/msgid/20250122-hblank-v9-1-90afda006685@intel.com --- diff --git a/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c b/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c index 36076e8d639bc..ecd0d9853c60f 100644 --- a/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c +++ b/drivers/gpu/drm/i915/display/intel_crtc_state_dump.c @@ -249,6 +249,7 @@ void intel_crtc_state_dump(const struct intel_crtc_state *pipe_config, str_enabled_disabled(pipe_config->has_sel_update), str_enabled_disabled(pipe_config->has_panel_replay), str_enabled_disabled(pipe_config->enable_psr2_sel_fetch)); + drm_printf(&p, "minimum HBlank: %d\n", pipe_config->min_hblank); } drm_printf(&p, "audio: %i, infoframes: %i, infoframes enabled: 0x%x\n", diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h index cb51b7936f933..f1a9ab4ae85a6 100644 --- a/drivers/gpu/drm/i915/display/intel_display_types.h +++ b/drivers/gpu/drm/i915/display/intel_display_types.h @@ -1097,6 +1097,7 @@ struct intel_crtc_state { int max_link_bpp_x16; /* in 1/16 bpp units */ int pipe_bpp; /* in 1 bpp units */ + int min_hblank; struct intel_link_m_n dp_m_n; /* m2_n2 for eDP downclock */ diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 7e58b9464a243..b8f4618d59839 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -209,6 +209,28 @@ static int intel_dp_mst_dsc_get_slice_count(const struct intel_connector *connec num_joined_pipes); } +static void intel_dp_mst_compute_min_hblank(struct intel_crtc_state *crtc_state, + struct intel_connector *connector, + int bpp_x16) +{ + struct intel_encoder *encoder = connector->encoder; + struct intel_display *display = to_intel_display(encoder); + const struct drm_display_mode *adjusted_mode = + &crtc_state->hw.adjusted_mode; + int symbol_size = intel_dp_is_uhbr(crtc_state) ? 32 : 8; + int hblank; + + if (DISPLAY_VER(display) < 20) + return; + + /* Calculate min Hblank Link Layer Symbol Cycle Count for 8b/10b MST & 128b/132b */ + hblank = DIV_ROUND_UP((DIV_ROUND_UP + (adjusted_mode->htotal - adjusted_mode->hdisplay, 4) * bpp_x16), + symbol_size); + + crtc_state->min_hblank = hblank; +} + int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp, struct intel_crtc_state *crtc_state, struct drm_connector_state *conn_state, @@ -278,6 +300,9 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp, local_bw_overhead = intel_dp_mst_bw_overhead(crtc_state, false, dsc_slice_count, link_bpp_x16); + + intel_dp_mst_compute_min_hblank(crtc_state, connector, link_bpp_x16); + intel_dp_mst_compute_m_n(crtc_state, local_bw_overhead, link_bpp_x16, @@ -967,6 +992,7 @@ static void mst_stream_disable(struct intel_atomic_state *state, struct intel_dp *intel_dp = to_primary_dp(encoder); struct intel_connector *connector = to_intel_connector(old_conn_state->connector); + enum transcoder trans = old_crtc_state->cpu_transcoder; drm_dbg_kms(display->drm, "active links %d\n", intel_dp->active_mst_links); @@ -977,6 +1003,8 @@ static void mst_stream_disable(struct intel_atomic_state *state, intel_hdcp_disable(intel_mst->connector); intel_dp_sink_disable_decompression(state, connector, old_crtc_state); + + intel_de_write(display, DP_MIN_HBLANK_CTL(trans), 0x00); } static void mst_stream_post_disable(struct intel_atomic_state *state, @@ -1249,7 +1277,7 @@ static void mst_stream_enable(struct intel_atomic_state *state, enum transcoder trans = pipe_config->cpu_transcoder; bool first_mst_stream = intel_dp->active_mst_links == 1; struct intel_crtc *pipe_crtc; - int ret, i; + int ret, i, min_hblank; drm_WARN_ON(display->drm, pipe_config->has_pch_encoder); @@ -1264,6 +1292,29 @@ static void mst_stream_enable(struct intel_atomic_state *state, TRANS_DP2_VFREQ_PIXEL_CLOCK(crtc_clock_hz & 0xffffff)); } + if (DISPLAY_VER(display) >= 20) { + /* + * adjust the BlankingStart/BlankingEnd framing control from + * the calculated value + */ + min_hblank = pipe_config->min_hblank - 2; + + /* Maximum value to be programmed is limited to 0x10 */ + min_hblank = min(0x10, min_hblank); + + /* + * Minimum hblank accepted for 128b/132b would be 5 and for + * 8b/10b would be 3 symbol count + */ + if (intel_dp_is_uhbr(pipe_config)) + min_hblank = max(min_hblank, 5); + else + min_hblank = max(min_hblank, 3); + + intel_de_write(display, DP_MIN_HBLANK_CTL(trans), + min_hblank); + } + enable_bs_jitter_was(pipe_config); intel_ddi_enable_transcoder_func(encoder, pipe_config); diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 03da51b03fb90..670cd2371f947 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3198,6 +3198,10 @@ #define _TRANS_DP2_VFREQLOW_D 0x630a8 #define TRANS_DP2_VFREQLOW(trans) _MMIO_TRANS(trans, _TRANS_DP2_VFREQLOW_A, _TRANS_DP2_VFREQLOW_B) +#define _DP_MIN_HBLANK_CTL_A 0x600ac +#define _DP_MIN_HBLANK_CTL_B 0x610ac +#define DP_MIN_HBLANK_CTL(trans) _MMIO_TRANS(trans, _DP_MIN_HBLANK_CTL_A, _DP_MIN_HBLANK_CTL_B) + /* SNB eDP training params */ /* SNB A-stepping */ #define EDP_LINK_TRAIN_400MV_0DB_SNB_A (0x38 << 22)