From: Clint Taylor <clinton.a.taylor@xxxxxxxxx> Several major vendor USB-C->HDMI converters fail to recover a 5.4 GHz 1 lane signal if the Data Link N is greater than 0x80000. Patch detects when 1 lane 5.4 GHz signal is being used and makes the maximum value 20 bit instead of the maximum specification supported 24 bit value. v2: Detect specific device that exhibits the issue. Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> Cc: Jani Nikula <jani.nikula@xxxxxxxxx> Cc: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93578 Signed-off-by: Clint Taylor <clinton.a.taylor@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.h | 3 ++- drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_display.c | 20 ++++++++++++++------ drivers/gpu/drm/i915/intel_dp.c | 14 ++++++++++++-- drivers/gpu/drm/i915/intel_dp_mst.c | 3 ++- 5 files changed, 32 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index a5947a4..6869df9 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -580,7 +580,8 @@ struct intel_link_m_n { void intel_link_compute_m_n(int bpp, int nlanes, int pixel_clock, int link_clock, - struct intel_link_m_n *m_n); + struct intel_link_m_n *m_n, + bool reduced_n); /* Interface history: * diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 04c8f69..838d8d5 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -4869,6 +4869,8 @@ enum { #define DATA_LINK_M_N_MASK (0xffffff) #define DATA_LINK_N_MAX (0x800000) +/* Maximum N value useable on some DP->HDMI converters */ +#define DATA_LINK_REDUCED_N_MAX (0x80000) #define _PIPEA_DATA_N_G4X 0x70054 #define _PIPEB_DATA_N_G4X 0x71054 diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 010e5dd..143c7ac 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -6139,7 +6139,7 @@ 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, - link_bw, &pipe_config->fdi_m_n); + link_bw, &pipe_config->fdi_m_n, false); ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config); if (ret == -EINVAL && pipe_config->pipe_bpp > 6*3) { @@ -6315,9 +6315,10 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc, } static void compute_m_n(unsigned int m, unsigned int n, - uint32_t *ret_m, uint32_t *ret_n) + uint32_t *ret_m, uint32_t *ret_n, + uint32_t max_link_n) { - *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX); + *ret_n = min_t(unsigned int, roundup_pow_of_two(n), max_link_n); *ret_m = div_u64((uint64_t) m * *ret_n, n); intel_reduce_m_n_ratio(ret_m, ret_n); } @@ -6325,16 +6326,23 @@ static void compute_m_n(unsigned int m, unsigned int n, void intel_link_compute_m_n(int bits_per_pixel, int nlanes, int pixel_clock, int link_clock, - struct intel_link_m_n *m_n) + struct intel_link_m_n *m_n, + bool reduced_n) { + uint32_t max_link_n = DATA_LINK_N_MAX; m_n->tu = 64; + if ((reduced_n) && (nlanes == 1) && (link_clock >= 540000)) + max_link_n = DATA_LINK_REDUCED_N_MAX; + compute_m_n(bits_per_pixel * pixel_clock, link_clock * nlanes * 8, - &m_n->gmch_m, &m_n->gmch_n); + &m_n->gmch_m, &m_n->gmch_n, + max_link_n); compute_m_n(pixel_clock, link_clock, - &m_n->link_m, &m_n->link_n); + &m_n->link_m, &m_n->link_n, + max_link_n); } static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index fd96a6c..9c96f5f 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1624,6 +1624,8 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp, int common_rates[DP_MAX_SUPPORTED_RATES] = {}; int common_len; uint8_t link_bw, rate_select; + char id[6]; + bool reduced_n = false; common_len = intel_dp_common_rates(intel_dp, common_rates); @@ -1750,10 +1752,17 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp, DRM_DEBUG_KMS("DP link bw required %i available %i\n", mode_rate, link_avail); + /* Quirk to detect DP->HDMI converter */ + drm_dp_downstream_id(&intel_dp->aux, id); + if (!strncmp(id , "7737" ,4)) { + reduced_n = true; + } + intel_link_compute_m_n(bpp, lane_count, adjusted_mode->crtc_clock, pipe_config->port_clock, - &pipe_config->dp_m_n); + &pipe_config->dp_m_n, + reduced_n); if (intel_connector->panel.downclock_mode != NULL && dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) { @@ -1761,7 +1770,8 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp, intel_link_compute_m_n(bpp, lane_count, intel_connector->panel.downclock_mode->clock, pipe_config->port_clock, - &pipe_config->dp_m2_n2); + &pipe_config->dp_m2_n2, + reduced_n); } /* diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index 094cbdc..3303767 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -75,7 +75,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, intel_link_compute_m_n(bpp, lane_count, adjusted_mode->crtc_clock, pipe_config->port_clock, - &pipe_config->dp_m_n); + &pipe_config->dp_m_n, + false); pipe_config->dp_m_n.tu = slots; -- 1.7.9.5 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
