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charset="utf-8" As per DisplayID v2.0 Errata E9 spec "DSC pass-through timing support" VESA vendor-specific data block may contain target DSC bits per pixel fields Signed-off-by: Yaroslav Bolyukin --- drivers/gpu/drm/drm_displayid_internal.h | 8 ++++ drivers/gpu/drm/drm_edid.c | 61 ++++++++++++++++-------- include/drm/drm_connector.h | 6 +++ include/drm/drm_modes.h | 10 ++++ 4 files changed, 64 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm= _displayid_internal.h index 957dd0619f5c..d008a98994bb 100644 --- a/drivers/gpu/drm/drm_displayid_internal.h +++ b/drivers/gpu/drm/drm_displayid_internal.h @@ -97,6 +97,10 @@ struct displayid_header { u8 ext_count; } __packed; =20 +#define DISPLAYID_BLOCK_REV GENMASK(2, 0) +#define DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT BIT(3) +#define DISPLAYID_BLOCK_DESCRIPTOR_PAYLOAD_BYTES GENMASK(6, 4) + struct displayid_block { u8 tag; u8 rev; @@ -144,12 +148,16 @@ struct displayid_formula_timing_block { =20 #define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0) #define DISPLAYID_VESA_MSO_MODE GENMASK(6, 5) +#define DISPLAYID_VESA_DSC_BPP_INT GENMASK(5, 0) +#define DISPLAYID_VESA_DSC_BPP_FRACT GENMASK(3, 0) =20 struct displayid_vesa_vendor_specific_block { struct displayid_block base; u8 oui[3]; u8 data_structure_type; u8 mso; + u8 dsc_bpp_int; + u8 dsc_bpp_fract; } __packed; =20 /* diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index e2e85345aa9a..6e42e55b41f9 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -6524,8 +6524,8 @@ static void drm_get_monitor_range(struct drm_connecto= r *connector, info->monitor_range.min_vfreq, info->monitor_range.max_vfreq); } =20 -static void drm_parse_vesa_mso_data(struct drm_connector *connector, - const struct displayid_block *block) +static void drm_parse_vesa_specific_block(struct drm_connector *connector, + const struct displayid_block *block) { struct displayid_vesa_vendor_specific_block *vesa =3D (struct displayid_vesa_vendor_specific_block *)block; @@ -6541,7 +6541,7 @@ static void drm_parse_vesa_mso_data(struct drm_connec= tor *connector, if (oui(vesa->oui[0], vesa->oui[1], vesa->oui[2]) !=3D VESA_IEEE_OUI) return; =20 - if (sizeof(*vesa) !=3D sizeof(*block) + block->num_bytes) { + if (block->num_bytes < 5) { drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] Unexpected VESA vendor block size\n", connector->base.id, connector->name); @@ -6564,28 +6564,40 @@ static void drm_parse_vesa_mso_data(struct drm_conn= ector *connector, break; } =20 - if (!info->mso_stream_count) { - info->mso_pixel_overlap =3D 0; - return; - } + info->mso_pixel_overlap =3D 0; =20 - info->mso_pixel_overlap =3D FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->m= so); - if (info->mso_pixel_overlap > 8) { - drm_dbg_kms(connector->dev, - "[CONNECTOR:%d:%s] Reserved MSO pixel overlap value %u\n", - connector->base.id, connector->name, - info->mso_pixel_overlap); - info->mso_pixel_overlap =3D 8; + if (info->mso_stream_count) { + info->mso_pixel_overlap =3D FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->= mso); + if (info->mso_pixel_overlap > 8) { + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] Reserved MSO pixel overlap value %u\n", + connector->base.id, connector->name, + info->mso_pixel_overlap); + info->mso_pixel_overlap =3D 8; + } } =20 drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] MSO stream count %u, pixel overlap %u\n", connector->base.id, connector->name, info->mso_stream_count, info->mso_pixel_overlap); + + if (block->num_bytes < 7) { + /* DSC bpp is optional */ + return; + } + + info->dp_dsc_bpp =3D FIELD_GET(DISPLAYID_VESA_DSC_BPP_INT, vesa->dsc_bpp_= int) << 4 | + FIELD_GET(DISPLAYID_VESA_DSC_BPP_FRACT, vesa->dsc_bpp_fract); + + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] DSC bits per pixel %u\n", + connector->base.id, connector->name, + info->dp_dsc_bpp); } =20 -static void drm_update_mso(struct drm_connector *connector, - const struct drm_edid *drm_edid) +static void drm_update_vesa_specific_block(struct drm_connector *connector, + const struct drm_edid *drm_edid) { const struct displayid_block *block; struct displayid_iter iter; @@ -6593,7 +6605,7 @@ static void drm_update_mso(struct drm_connector *conn= ector, displayid_iter_edid_begin(drm_edid, &iter); displayid_iter_for_each(block, &iter) { if (block->tag =3D=3D DATA_BLOCK_2_VENDOR_SPECIFIC) - drm_parse_vesa_mso_data(connector, block); + drm_parse_vesa_specific_block(connector, block); } displayid_iter_end(&iter); } @@ -6630,6 +6642,7 @@ static void drm_reset_display_info(struct drm_connect= or *connector) info->mso_stream_count =3D 0; info->mso_pixel_overlap =3D 0; info->max_dsc_bpp =3D 0; + info->dp_dsc_bpp =3D 0; =20 kfree(info->vics); info->vics =3D NULL; @@ -6753,7 +6766,7 @@ static void update_display_info(struct drm_connector = *connector, if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB422) info->color_formats |=3D DRM_COLOR_FORMAT_YCBCR422; =20 - drm_update_mso(connector, drm_edid); + drm_update_vesa_specific_block(connector, drm_edid); =20 out: if (drm_edid_has_internal_quirk(connector, EDID_QUIRK_NON_DESKTOP)) { @@ -6784,7 +6797,8 @@ static void update_display_info(struct drm_connector = *connector, =20 static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_dev= ice *dev, const struct displayid_detailed_timings_1 *timings, - bool type_7) + bool type_7, + int rev) { struct drm_display_mode *mode; unsigned int pixel_clock =3D (timings->pixel_clock[0] | @@ -6805,6 +6819,10 @@ static struct drm_display_mode *drm_mode_displayid_d= etailed(struct drm_device *d if (!mode) return NULL; =20 + if (type_7 && FIELD_GET(DISPLAYID_BLOCK_REV, rev) >=3D 1) + mode->dsc_passthrough_timings_support =3D + !!(rev & DISPLAYID_BLOCK_PASSTHROUGH_TIMINGS_SUPPORT); + /* resolution is kHz for type VII, and 10 kHz for type I */ mode->clock =3D type_7 ? pixel_clock : pixel_clock * 10; mode->hdisplay =3D hactive; @@ -6846,7 +6864,7 @@ static int add_displayid_detailed_1_modes(struct drm_= connector *connector, for (i =3D 0; i < num_timings; i++) { struct displayid_detailed_timings_1 *timings =3D &det->timings[i]; =20 - newmode =3D drm_mode_displayid_detailed(connector->dev, timings, type_7); + newmode =3D drm_mode_displayid_detailed(connector->dev, timings, type_7,= block->rev); if (!newmode) continue; =20 @@ -6893,7 +6911,8 @@ static int add_displayid_formula_modes(struct drm_con= nector *connector, struct drm_display_mode *newmode; int num_modes =3D 0; bool type_10 =3D block->tag =3D=3D DATA_BLOCK_2_TYPE_10_FORMULA_TIMING; - int timing_size =3D 6 + ((formula_block->base.rev & 0x70) >> 4); + int timing_size =3D 6 + + FIELD_GET(DISPLAYID_BLOCK_DESCRIPTOR_PAYLOAD_BYTES, formula_block->base.= rev); =20 /* extended blocks are not supported yet */ if (timing_size !=3D 6) diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 8f34f4b8183d..01640fcf7464 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -837,6 +837,12 @@ struct drm_display_info { */ u32 max_dsc_bpp; =20 + /** + * @dp_dsc_bpp: DP Display-Stream-Compression (DSC) timing's target + * DSC bits per pixel in 6.4 fixed point format. 0 means undefined. + */ + u16 dp_dsc_bpp; + /** * @vics: Array of vics_len VICs. 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d=lach.pw; c=relaxed/relaxed; h=Message-ID:Date:Subject:To:From; t=1760573500; bh=89tz8HOxoS8Ul81Dor63mIb eoHc7opGGFVAFrfMdieA=; b=P3fIws/qQFT2boo0kZuHGd32xA/PGpsCKzMAqKuyXBgCkQlEFt F3+OP/rNONLl5TViA3ktIl/TMDBmgdSXLCAg==; From: Yaroslav Bolyukin To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Cc: Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , =?UTF-8?q?Christian=20K=C3=B6nig?= , Wayne Lin , amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Yaroslav Bolyukin Subject: [PATCH v4 2/2] drm/amd: use fixed dsc bits-per-pixel from edid Date: Thu, 16 Oct 2025 02:10:41 +0200 Message-ID: <20251016001038.13611-6-iam@lach.pw> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251016001038.13611-2-iam@lach.pw> References: <20251016001038.13611-2-iam@lach.pw> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" VESA vendor header from DisplayID spec may contain fixed bit per pixel rate, it should be respected by drm driver Signed-off-by: Yaroslav Bolyukin --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gp= u/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 0d03e324d5b9..ebe5bb4eecf8 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6521,6 +6521,11 @@ static void fill_stream_properties_from_drm_display_= mode( =20 stream->output_color_space =3D get_output_color_space(timing_out, connect= or_state); stream->content_type =3D get_output_content_type(connector_state); + + /* DisplayID Type VII pass-through timings. */ + if (mode_in->dsc_passthrough_timings_support && info->dp_dsc_bpp !=3D 0) { + stream->timing.dsc_fixed_bits_per_pixel_x16 =3D info->dp_dsc_bpp; + } } =20 static void fill_audio_info(struct audio_info *audio_info, @@ -7067,6 +7072,13 @@ create_stream_for_sink(struct drm_connector *connect= or, &mode, preferred_mode, scale); =20 preferred_refresh =3D drm_mode_vrefresh(preferred_mode); + + /* + * HACK: In case of multiple supported modes, we should look at the mat= ching mode to decide this flag. + * But what is matching mode, how should it be decided? + * Assuming that only preferred mode would have this flag. + */ + mode.dsc_passthrough_timings_support =3D preferred_mode->dsc_passthroug= h_timings_support; } } =20 @@ -7756,7 +7768,7 @@ create_validate_stream_for_sink(struct drm_connector = *connector, drm_dbg_kms(connector->dev, "%s:%d Validation failed with %d, retrying = w/ YUV420\n", __func__, __LINE__, dc_result); aconnector->force_yuv420_output =3D true; - } +} stream =3D create_validate_stream_for_sink(connector, drm_mode, dm_state, old_stream); aconnector->force_yuv422_output =3D false; --=20 2.51.0