From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A58F0CD5BD2 for ; Tue, 26 May 2026 10:20:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E898A10E483; Tue, 26 May 2026 10:20:53 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="aXlxj9tz"; dkim-atps=neutral Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3AA5F10E483 for ; Tue, 26 May 2026 10:20:52 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; t=1779790844; cv=none; d=zohomail.com; s=zohoarc; b=ey6m8N7ArfNq2XH8DX8PPytfMh5yuFDb2twFWemCg5SgQPdzsInkHps0RHP8G9KWUKJXHit77RAAOdl4xjVQeMmddED/JSpX7Ewb1j4wPESNEMBZCYMijcTWf/wGvHI+A548zL0ljpCCwh8r31mJo0EYnL0SbXbrwHQ7B8jMRPk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790844; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=8Bw44yj8ihcngpOzwLFcKybQ58rRbVJiSI4XfPqPIcQ=; b=mn1tHh4Kt0ozLeVM5KKQP2zb4yYXM2ujZ5gmD0ouliBX/32+GImSCPA5e4DGzRJH77kMla41d00Sn75lLX0s80kNmdUoJvEBOSoENmvk0Vsn5vAyOW/jyHuUEZ6Bi4KON1+Gspx+f8IKzTPEJhbbOfzNHNALmPchSeDQSlryIvs= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790844; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=8Bw44yj8ihcngpOzwLFcKybQ58rRbVJiSI4XfPqPIcQ=; b=aXlxj9tz4V31K77CofN/w8J+i4aXO0W0RgIjcB2WGkZXoBRq8BaAxsO/q5l7Y26d Z/fgE6AluteCJiq/YXADUcQl5q9oehR/Mz13vog7DKQMZNTrfiHV2h2pjFie7aqmqod TykbPmPgvMAyhMeU+IGxtUGqk1p6Wz0cwQBnNlSY= Received: by mx.zohomail.com with SMTPS id 1779790841806739.2556066328924; Tue, 26 May 2026 03:20:41 -0700 (PDT) From: Nicolas Frattaroli Date: Tue, 26 May 2026 12:20:00 +0200 Subject: [PATCH v3 4/4] drm/scdc-helper: Implement parsing and printing HDMI 2.1 fields MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260526-scdc-link-health-v3-4-59e4a4aaead1@collabora.com> References: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> In-Reply-To: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.15.2 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" HDMI 2.1 redefines previously reserved fields in SCDC for various new uses. No version check needs to be performed, as an HDMI 2.0 sink's reserved SCDC fields are well-defined to be 0, and any zero-ness of these fields for an HDMI 2.0 sink is not a surprise for SCDC parsers for HDMI 2.1. Implement reading and outputting these fields over debugfs. Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/display/drm_scdc_helper.c | 154 ++++++++++++++++++++++++++---- include/drm/display/drm_scdc.h | 9 ++ include/drm/display/drm_scdc_helper.h | 85 ++++++++++++++--- 3 files changed, 218 insertions(+), 30 deletions(-) diff --git a/drivers/gpu/drm/display/drm_scdc_helper.c b/drivers/gpu/drm/display/drm_scdc_helper.c index 75a59c6fc7a5..b5a866372b0f 100644 --- a/drivers/gpu/drm/display/drm_scdc_helper.c +++ b/drivers/gpu/drm/display/drm_scdc_helper.c @@ -21,6 +21,7 @@ * DEALINGS IN THE SOFTWARE. */ +#include #include #include #include @@ -63,6 +64,38 @@ struct scdc_debugfs_priv { struct drm_scdc_state state; }; +static __pure const char *drm_scdc_frl_rate_str(enum drm_scdc_frl_rate rate) +{ + switch (rate) { + case SCDC_FRL_RATE_OFF: + return "Off"; + case SCDC_FRL_RATE_3X3: + return "3 Gbit/s x 3 lanes"; + case SCDC_FRL_RATE_6X3: + return "6 Gbit/s x 3 lanes"; + case SCDC_FRL_RATE_6X4: + return "6 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_8X4: + return "8 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_10X4: + return "10 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_12X4: + return "12 Gbit/s x 4 lanes"; + case SCDC_FRL_RATE_RESV_7: + case SCDC_FRL_RATE_RESV_8: + case SCDC_FRL_RATE_RESV_9: + case SCDC_FRL_RATE_RESV_10: + case SCDC_FRL_RATE_RESV_11: + case SCDC_FRL_RATE_RESV_12: + case SCDC_FRL_RATE_RESV_13: + case SCDC_FRL_RATE_RESV_14: + case SCDC_FRL_RATE_RESV_15: + return "(Reserved)"; + default: + return NULL; + } +} + /** * drm_scdc_read - read a block of data from SCDC * @adapter: I2C controller @@ -309,10 +342,57 @@ int drm_scdc_read_status0_flags(struct drm_connector *connector, } EXPORT_SYMBOL(drm_scdc_read_status0_flags); +/** + * drm_scdc_read_status1_2_flags - Read SCDC "Status Flags" 1 and 2 Registers + * @connector: pointer to &struct drm_connector to issue the scdc request on + * @flags: pointer to the caller's &struct drm_scdc_status_flags to output to + * + * Reads the SCDC Status Flags 1 and 2 registers, and outputs their contents to + * the destination @flags. Contents of @flags.status1 and @flags.status2 are + * only valid if function returns 0. + * + * Returns 0 on success, negative errno on error. + */ +int drm_scdc_read_status1_2_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags) +{ + int ret; + + ret = drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_FLT_UPDATE); + if (ret) + return ret; + + ret = drm_scdc_readb(connector->ddc, SCDC_STATUS_FLAGS_1, &flags->status1.data); + if (ret) + return ret; + + return drm_scdc_readb(connector->ddc, SCDC_STATUS_FLAGS_2, &flags->status2.data); +} +EXPORT_SYMBOL(drm_scdc_read_status1_2_flags); + +#define ERR_DET_OFF(x) ((x) - SCDC_ERR_DET_0_L) + +static int __pure scdc_err_cnt_buf_idx(unsigned int lane) +{ + switch (lane) { + case 0: + return ERR_DET_OFF(SCDC_ERR_DET_0_L); + case 1: + return ERR_DET_OFF(SCDC_ERR_DET_1_L); + case 2: + return ERR_DET_OFF(SCDC_ERR_DET_2_L); + case 3: + return ERR_DET_OFF(SCDC_ERR_DET_3_L); + default: + return -EINVAL; + } +} + /** * drm_scdc_read_error_counters - Read and clear SCDC error counters * @connector: pointer to &struct drm_connector to issue the scdc request on - * @counter: Caller's u16 array with 3 elements to write the counter values into + * @counter: Caller's u16 array with 4 elements to write the counter values into + * @num_lanes: number of active lanes, either 3 or 4 * * Read the SCDC channel error counters. If the count of channel *n* is valid, * write it into counter[n]. Otherwise, set counter[n] to 0. Reads all counters @@ -320,18 +400,31 @@ EXPORT_SYMBOL(drm_scdc_read_status0_flags); * * Returns: %0 on success, negative errno on error. */ -int drm_scdc_read_error_counters(struct drm_connector *connector, u16 counter[3]) +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 counter[4], + unsigned int num_lanes) { - u8 buf[7] = { 0 }; + unsigned int buf_sz; + u8 buf[9] = { 0 }; int ret; u8 sum = 0; - int i; + int i, idx; + + switch (num_lanes) { + case 3: + buf_sz = 7; + break; + case 4: + buf_sz = 9; + break; + default: + return -EINVAL; + } ret = drm_scdc_writeb(connector->ddc, SCDC_UPDATE_0, SCDC_CED_UPDATE); if (ret) return ret; - ret = drm_scdc_read(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(buf)); + ret = drm_scdc_read(connector->ddc, SCDC_ERR_DET_0_L, buf, buf_sz); if (ret) return ret; @@ -339,24 +432,23 @@ int drm_scdc_read_error_counters(struct drm_connector *connector, u16 counter[3] * Verify the "checksum", i.e. sum up everything including the checksum * register as a wrapping unsigned 8-bit addition and verify it's 0. */ - for (i = 0; i < ARRAY_SIZE(buf); i++) + for (i = 0; i < buf_sz; i++) sum = wrapping_add(u8, sum, buf[i]); if (sum) return -EPROTO; - for (i = 0; i < ARRAY_SIZE(buf) - 1; i += 2) { - if (buf[i + 1] & SCDC_CHANNEL_VALID) - counter[i / 2] = buf[i] | (buf[i + 1] & ~SCDC_CHANNEL_VALID) << 8; + for (i = 0; i < num_lanes; i++) { + idx = scdc_err_cnt_buf_idx(i); + if (buf[idx + 1] & SCDC_CHANNEL_VALID) + counter[i] = buf[idx] | (buf[idx + 1] & ~SCDC_CHANNEL_VALID) << 8; else - counter[i / 2] = 0; - - buf[i] = 0; - buf[i + 1] = 0; + counter[i] = 0; } - buf[ARRAY_SIZE(buf) - 1] = 0; - return drm_scdc_write(connector->ddc, SCDC_ERR_DET_0_L, buf, ARRAY_SIZE(buf)); + memset(buf, 0, buf_sz); + + return drm_scdc_write(connector->ddc, SCDC_ERR_DET_0_L, buf, buf_sz); } EXPORT_SYMBOL(drm_scdc_read_error_counters); @@ -376,6 +468,7 @@ int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_state * u8 upd_flags[2] = { 0 }; struct i2c_adapter *ddc; struct drm_scdc *scdc; + int num_lanes; int ret; u8 val; @@ -397,6 +490,19 @@ int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_state * state->scrambling_detected = drm_scdc_get_scrambling_status(connector); + ret = drm_scdc_readb(ddc, SCDC_CONFIG_1, &val); + if (ret) + return ret; + + state->rate = FIELD_GET(SCDC_FRL_RATE, val); + num_lanes = drm_scdc_num_frl_lanes(state->rate); + if (num_lanes < 0) + return num_lanes; + if (!num_lanes) + num_lanes = 3; + + state->ffe_levels = FIELD_GET(SCDC_FFE_LEVELS, val); + ret = drm_scdc_read(ddc, SCDC_UPDATE_0, &upd_flags, sizeof(upd_flags)); if (ret) return ret; @@ -407,8 +513,15 @@ int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_state * return ret; } + if (upd_flags[0] & SCDC_FLT_UPDATE) { + ret = drm_scdc_read_status1_2_flags(connector, &state->stf); + if (ret) + return ret; + } + if (upd_flags[0] & SCDC_CED_UPDATE) { - ret = drm_scdc_read_error_counters(connector, state->error_count); + ret = drm_scdc_read_error_counters(connector, state->error_count, + num_lanes); if (ret) return ret; } @@ -456,6 +569,8 @@ static int scdc_status_show(struct seq_file *m, void *data) scdc_print_flag(m, "Scrambling Enabled", st->scrambling_enabled); scdc_print_flag(m, "Scrambling Detected", st->scrambling_detected); + scdc_print_str(m, "FRL Rate", drm_scdc_frl_rate_str(st->rate)); + scdc_print_dec(m, "FFE Levels", st->ffe_levels); if (st->tmds_bclk_x40) scdc_print_str(m, "TMDS Bit Clock Ratio", "1/40"); @@ -466,10 +581,17 @@ static int scdc_status_show(struct seq_file *m, void *data) scdc_print_flag(m, "Channel 0 Locked", st->stf.status0.flags.ch0_locked); scdc_print_flag(m, "Channel 1 Locked", st->stf.status0.flags.ch1_locked); scdc_print_flag(m, "Channel 2 Locked", st->stf.status0.flags.ch2_locked); + if (drm_scdc_num_frl_lanes(st->rate) == 4) + scdc_print_flag(m, "Lane 3 Locked", st->stf.status0.flags.ln3_locked); + + scdc_print_flag(m, "Sink Ready For Link Training", st->stf.status0.flags.flt_ready); + scdc_print_flag(m, "Sink Failed To Decode DSC", st->stf.status0.flags.dsc_fail); scdc_print_dec(m, "Channel 0 Errors", st->error_count[0]); scdc_print_dec(m, "Channel 1 Errors", st->error_count[1]); scdc_print_dec(m, "Channel 2 Errors", st->error_count[2]); + if (drm_scdc_num_frl_lanes(st->rate) == 4) + scdc_print_dec(m, "Lane 3 Errors", st->error_count[3]); return 0; diff --git a/include/drm/display/drm_scdc.h b/include/drm/display/drm_scdc.h index 3d58f37e8ed8..56cd909edac9 100644 --- a/include/drm/display/drm_scdc.h +++ b/include/drm/display/drm_scdc.h @@ -29,6 +29,7 @@ #define SCDC_SOURCE_VERSION 0x02 #define SCDC_UPDATE_0 0x10 +#define SCDC_FLT_UPDATE (1 << 5) #define SCDC_READ_REQUEST_TEST (1 << 2) #define SCDC_CED_UPDATE (1 << 1) #define SCDC_STATUS_UPDATE (1 << 0) @@ -46,6 +47,10 @@ #define SCDC_CONFIG_0 0x30 #define SCDC_READ_REQUEST_ENABLE (1 << 0) +#define SCDC_CONFIG_1 0x31 +#define SCDC_FRL_RATE 0x0f +#define SCDC_FFE_LEVELS 0xf0 + #define SCDC_STATUS_FLAGS_0 0x40 #define SCDC_CH2_LOCK (1 << 3) #define SCDC_CH1_LOCK (1 << 2) @@ -54,6 +59,7 @@ #define SCDC_CLOCK_DETECT (1 << 0) #define SCDC_STATUS_FLAGS_1 0x41 +#define SCDC_STATUS_FLAGS_2 0x42 #define SCDC_ERR_DET_0_L 0x50 #define SCDC_ERR_DET_0_H 0x51 @@ -65,6 +71,9 @@ #define SCDC_ERR_DET_CHECKSUM 0x56 +#define SCDC_ERR_DET_3_L 0x57 +#define SCDC_ERR_DET_3_H 0x58 + #define SCDC_TEST_CONFIG_0 0xc0 #define SCDC_TEST_READ_REQUEST (1 << 7) #define SCDC_TEST_READ_REQUEST_DELAY(x) ((x) & 0x7f) diff --git a/include/drm/display/drm_scdc_helper.h b/include/drm/display/drm_scdc_helper.h index c066c1158275..a1b73f0be73f 100644 --- a/include/drm/display/drm_scdc_helper.h +++ b/include/drm/display/drm_scdc_helper.h @@ -24,6 +24,7 @@ #ifndef DRM_SCDC_HELPER_H #define DRM_SCDC_HELPER_H +#include #include #include @@ -40,10 +41,10 @@ struct drm_scdc_status_flags { bool ch0_locked : 1; bool ch1_locked : 1; bool ch2_locked : 1; - bool rsvd_4 : 1; + bool ln3_locked : 1; bool rsvd_5 : 1; - bool rsvd_6 : 1; - bool rsvd_7 : 1; + bool flt_ready : 1; + bool dsc_fail : 1; } flags __packed; u8 data; } status0; @@ -51,19 +52,68 @@ struct drm_scdc_status_flags { /* Status Register 1 */ union { struct { - bool rsvd_0 : 1; - bool rsvd_1 : 1; - bool rsvd_2 : 1; - bool rsvd_3 : 1; - bool rsvd_4 : 1; - bool rsvd_5 : 1; - bool rsvd_6 : 1; - bool rsvd_7 : 1; + u8 ln0_training_pattern : 4; + u8 ln1_training_pattern : 4; } flags __packed; u8 data; } status1; + + /* Status Register 2 */ + union { + struct { + u8 ln2_training_pattern : 4; + u8 ln3_training_pattern : 4; + } flags __packed; + u8 data; + } status2; +}; + +enum drm_scdc_frl_rate { + SCDC_FRL_RATE_OFF = 0, + SCDC_FRL_RATE_3X3 = 1, + SCDC_FRL_RATE_6X3 = 2, + SCDC_FRL_RATE_6X4 = 3, + SCDC_FRL_RATE_8X4 = 4, + SCDC_FRL_RATE_10X4 = 5, + SCDC_FRL_RATE_12X4 = 6, + SCDC_FRL_RATE_RESV_7 = 7, + SCDC_FRL_RATE_RESV_8 = 8, + SCDC_FRL_RATE_RESV_9 = 9, + SCDC_FRL_RATE_RESV_10 = 10, + SCDC_FRL_RATE_RESV_11 = 11, + SCDC_FRL_RATE_RESV_12 = 12, + SCDC_FRL_RATE_RESV_13 = 13, + SCDC_FRL_RATE_RESV_14 = 14, + SCDC_FRL_RATE_RESV_15 = 15 }; +/** + * drm_scdc_num_frl_lanes - get number of lanes for a given FRL rate + * @rate: one of &enum drm_scdc_frl_rate + * + * For a given @rate, return the number of lanes it uses. + * + * Returns: %-EINVAL if @rate is not a valid FRL rate, or the number of lanes + * for a given &enum drm_scdc_frl_rate on success (including %0 for "off") + */ +static inline __pure int drm_scdc_num_frl_lanes(enum drm_scdc_frl_rate rate) +{ + switch (rate) { + case SCDC_FRL_RATE_OFF: + return 0; + case SCDC_FRL_RATE_3X3: + case SCDC_FRL_RATE_6X3: + return 3; + case SCDC_FRL_RATE_6X4: + case SCDC_FRL_RATE_8X4: + case SCDC_FRL_RATE_10X4: + case SCDC_FRL_RATE_12X4: + return 4; + default: + return -EINVAL; + } +} + struct drm_scdc_state { /** @stf: contents of the status flag registers */ struct drm_scdc_status_flags stf; @@ -76,8 +126,12 @@ struct drm_scdc_state { * clock period, false if it's 1/10th of the clock period. */ bool tmds_bclk_x40; - /** @error_count: character error counts for each channel */ - u16 error_count[3]; + /** @rate: FRL rate set by the source */ + enum drm_scdc_frl_rate rate : 4; + /** @ffe_levels: The FFE levels for @rate set by the source */ + u8 ffe_levels : 4; + /** @error_count: character error counts for each channel/link */ + u16 error_count[4]; }; int drm_scdc_read(struct i2c_adapter *adapter, u8 offset, void *buffer, @@ -128,9 +182,12 @@ bool drm_scdc_set_high_tmds_clock_ratio(struct drm_connector *connector, bool se int drm_scdc_read_status0_flags(struct drm_connector *connector, struct drm_scdc_status_flags *flags); +int drm_scdc_read_status1_2_flags(struct drm_connector *connector, + struct drm_scdc_status_flags *flags); int drm_scdc_read_state(struct drm_connector *connector, struct drm_scdc_state *state); -int drm_scdc_read_error_counters(struct drm_connector *connector, u16 counter[3]); +int drm_scdc_read_error_counters(struct drm_connector *connector, u16 counter[4], + unsigned int num_lanes); void drm_scdc_debugfs_init(struct drm_connector *connector, struct dentry *root); #endif -- 2.54.0