diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 3e5f52110ea1..213fb837e1c4 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -1208,3 +1208,86 @@ int drm_dp_stop_crc(struct drm_dp_aux *aux) return 0; } EXPORT_SYMBOL(drm_dp_stop_crc); + +struct dpcd_quirk { + u8 oui[3]; + bool is_branch; + u32 quirks; +}; + +#define OUI(first, second, third) { (first), (second), (third) } + +static const struct dpcd_quirk dpcd_quirk_list[] = { + /* Analogix 7737 needs reduced M and N at HBR2 link rates */ + { OUI(0x00, 0x22, 0xb9), true, BIT(DP_DPCD_QUIRK_LIMITED_M_N) }, +}; + +#undef OUI + +/* + * Get a bit mask of DPCD quirks for the sink/branch device identified by + * ident. The quirk data is shared but it's up to the drivers to act on the + * data. + * + * For now, only the OUI (first three bytes) is used, but this may be extended + * to device identification string and hardware/firmware revisions later. + */ +static u32 +drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch) +{ + const struct dpcd_quirk *quirk; + u32 quirks = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(dpcd_quirk_list); i++) { + quirk = &dpcd_quirk_list[i]; + + if (quirk->is_branch != is_branch) + continue; + + if (memcmp(quirk->oui, ident->oui, sizeof(ident->oui)) != 0) + continue; + + quirks |= quirk->quirks; + } + + return quirks; +} + +/** + * drm_dp_read_desc - read sink/branch descriptor from DPCD + * @aux: DisplayPort AUX channel + * @desc: Device decriptor to fill from DPCD + * @is_branch: true for branch devices, false for sink devices + * + * Read DPCD 0x400 (sink) or 0x500 (branch) into @desc. Also debug log the + * identification. + * + * Returns 0 on success or a negative error code on failure. + */ +int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc, + bool is_branch) +{ + struct drm_dp_dpcd_ident *ident = &desc->ident; + unsigned int offset = is_branch ? DP_BRANCH_OUI : DP_SINK_OUI; + int ret, dev_id_len; + + ret = drm_dp_dpcd_read(aux, offset, ident, sizeof(*ident)); + if (ret < 0) + return ret; + + desc->quirks = drm_dp_get_quirks(ident, is_branch); + + dev_id_len = strnlen(ident->device_id, sizeof(ident->device_id)); + + DRM_DEBUG_KMS("DP %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d quirks 0x%04x\n", + is_branch ? "branch" : "sink", + (int)sizeof(ident->oui), ident->oui, + dev_id_len, ident->device_id, + ident->hw_rev >> 4, ident->hw_rev & 0xf, + ident->sw_major_rev, ident->sw_minor_rev, + desc->quirks); + + return 0; +} +EXPORT_SYMBOL(drm_dp_read_desc); diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index c9b0949f6c1a..963f6d4481f7 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -562,7 +562,8 @@ 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 reduce_m_n); /* Interface history: * diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 3617927af269..3cabe52a4e3b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -6101,7 +6101,7 @@ retry: 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) { @@ -6277,7 +6277,8 @@ intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den) } 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, + bool reduce_m_n) { /* * Reduce M/N as much as possible without loss in precision. Several DP @@ -6285,9 +6286,11 @@ static void compute_m_n(unsigned int m, unsigned int n, * values. The passed in values are more likely to have the least * significant bits zero than M after rounding below, so do this first. */ - while ((m & 1) == 0 && (n & 1) == 0) { - m >>= 1; - n >>= 1; + if (reduce_m_n) { + while ((m & 1) == 0 && (n & 1) == 0) { + m >>= 1; + n >>= 1; + } } *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX); @@ -6298,16 +6301,19 @@ 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 reduce_m_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); + &m_n->gmch_m, &m_n->gmch_n, + reduce_m_n); compute_m_n(pixel_clock, link_clock, - &m_n->link_m, &m_n->link_n); + &m_n->link_m, &m_n->link_n, + reduce_m_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 ee77b519835c..fc691b8b317c 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1507,37 +1507,6 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp) DRM_DEBUG_KMS("common rates: %s\n", str); } -bool -__intel_dp_read_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc) -{ - u32 base = drm_dp_is_branch(intel_dp->dpcd) ? DP_BRANCH_OUI : - DP_SINK_OUI; - - return drm_dp_dpcd_read(&intel_dp->aux, base, desc, sizeof(*desc)) == - sizeof(*desc); -} - -bool intel_dp_read_desc(struct intel_dp *intel_dp) -{ - struct intel_dp_desc *desc = &intel_dp->desc; - bool oui_sup = intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] & - DP_OUI_SUPPORT; - int dev_id_len; - - if (!__intel_dp_read_desc(intel_dp, desc)) - return false; - - dev_id_len = strnlen(desc->device_id, sizeof(desc->device_id)); - DRM_DEBUG_KMS("DP %s: OUI %*phD%s dev-ID %*pE HW-rev %d.%d SW-rev %d.%d\n", - drm_dp_is_branch(intel_dp->dpcd) ? "branch" : "sink", - (int)sizeof(desc->oui), desc->oui, oui_sup ? "" : "(NS)", - dev_id_len, desc->device_id, - desc->hw_rev >> 4, desc->hw_rev & 0xf, - desc->sw_major_rev, desc->sw_minor_rev); - - return true; -} - static int rate_to_index(int find, const int *rates) { int i = 0; @@ -1624,6 +1593,8 @@ intel_dp_compute_config(struct intel_encoder *encoder, int common_rates[DP_MAX_SUPPORTED_RATES] = {}; int common_len; uint8_t link_bw, rate_select; + bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc, + DP_DPCD_QUIRK_LIMITED_M_N); common_len = intel_dp_common_rates(intel_dp, common_rates); @@ -1753,7 +1724,8 @@ found: 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, + reduce_m_n); if (intel_connector->panel.downclock_mode != NULL && dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) { @@ -1761,7 +1733,8 @@ found: 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, + reduce_m_n); } /* @@ -3622,7 +3595,8 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp) if (!intel_dp_read_dpcd(intel_dp)) return false; - intel_dp_read_desc(intel_dp); + drm_dp_read_desc(&intel_dp->aux, &intel_dp->desc, + drm_dp_is_branch(intel_dp->dpcd)); if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11) dev_priv->no_aux_handshake = intel_dp->dpcd[DP_MAX_DOWNSPREAD] & @@ -4624,7 +4598,8 @@ intel_dp_long_pulse(struct intel_connector *intel_connector) intel_dp_print_rates(intel_dp); - intel_dp_read_desc(intel_dp); + drm_dp_read_desc(&intel_dp->aux, &intel_dp->desc, + drm_dp_is_branch(intel_dp->dpcd)); intel_dp_configure_mst(intel_dp); diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index c1f62eb07c07..989e25577ac0 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -44,6 +44,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, int lane_count, slots; const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode; int mst_pbn; + bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc, + DP_DPCD_QUIRK_LIMITED_M_N); pipe_config->has_pch_encoder = false; bpp = 24; @@ -75,7 +77,8 @@ 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, + reduce_m_n); pipe_config->dp_m_n.tu = slots; diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index aaee3949a422..f630c7af5020 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -906,14 +906,6 @@ enum link_m_n_set { M2_N2 }; -struct intel_dp_desc { - u8 oui[3]; - u8 device_id[6]; - u8 hw_rev; - u8 sw_major_rev; - u8 sw_minor_rev; -} __packed; - struct intel_dp_compliance_data { unsigned long edid; uint8_t video_pattern; @@ -957,7 +949,7 @@ struct intel_dp { /* Max link BW for the sink as per DPCD registers */ int max_sink_link_bw; /* sink or branch descriptor */ - struct intel_dp_desc desc; + struct drm_dp_desc desc; struct drm_dp_aux aux; enum intel_display_power_domain aux_power_domain; uint8_t train_set[4]; @@ -1532,9 +1524,6 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count) } bool intel_dp_read_dpcd(struct intel_dp *intel_dp); -bool __intel_dp_read_desc(struct intel_dp *intel_dp, - struct intel_dp_desc *desc); -bool intel_dp_read_desc(struct intel_dp *intel_dp); int intel_dp_link_required(int pixel_clock, int bpp); int intel_dp_max_data_rate(int max_link_clock, int max_lanes); bool intel_digital_port_connected(struct drm_i915_private *dev_priv, diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c index 71cbe9c08932..5abef482eacf 100644 --- a/drivers/gpu/drm/i915/intel_lspcon.c +++ b/drivers/gpu/drm/i915/intel_lspcon.c @@ -240,7 +240,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port) return false; } - intel_dp_read_desc(dp); + drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd)); DRM_DEBUG_KMS("Success: LSPCON init\n"); return true; diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index c0bd0d7651a9..bb837310c07e 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -913,4 +913,55 @@ void drm_dp_aux_unregister(struct drm_dp_aux *aux); int drm_dp_start_crc(struct drm_dp_aux *aux, struct drm_crtc *crtc); int drm_dp_stop_crc(struct drm_dp_aux *aux); +struct drm_dp_dpcd_ident { + u8 oui[3]; + u8 device_id[6]; + u8 hw_rev; + u8 sw_major_rev; + u8 sw_minor_rev; +} __packed; + +/** + * struct drm_dp_desc - DP branch/sink device descriptor + * @ident: DP device identification from DPCD 0x400 (sink) or 0x500 (branch). + * @quirks: Quirks; use drm_dp_has_quirk() to query for the quirks. + */ +struct drm_dp_desc { + struct drm_dp_dpcd_ident ident; + u32 quirks; +}; + +int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc, + bool is_branch); + +/** + * enum drm_dp_quirk - Display Port sink/branch device specific quirks + * + * Display Port sink and branch devices in the wild have a variety of bugs, try + * to collect them here. The quirks are shared, but it's up to the drivers to + * implement workarounds for them. + */ +enum drm_dp_quirk { + /** + * @DP_DPCD_QUIRK_LIMITED_M_N: + * + * The device requires main link attributes Mvid and Nvid to be limited + * to 16 bits. + */ + DP_DPCD_QUIRK_LIMITED_M_N, +}; + +/** + * drm_dp_has_quirk() - does the DP device have a specific quirk + * @desc: Device decriptor filled by drm_dp_read_desc() + * @quirk: Quirk to query for + * + * Return true if DP device identified by @desc has @quirk. + */ +static inline bool +drm_dp_has_quirk(const struct drm_dp_desc *desc, enum drm_dp_quirk quirk) +{ + return desc->quirks & BIT(quirk); +} + #endif /* _DRM_DP_HELPER_H_ */