xr: add AMD DSC PPS debugfs diagnostic carry

.github/workflows/build-kernel.yml

@@ -116,6 +116,10 @@ jobs:
             .github
             xr
 
+      - name: Check XR patch wiring
+        if: steps.filter.outputs.skip != 'true'
+        run: bash xr/scripts/check-rpm-patch-wiring.sh
+
       - name: Restore ccache
         if: steps.filter.outputs.skip != 'true' && (github.event_name != 'workflow_dispatch' || inputs.use_ccache == 'true')
         uses: actions/cache/restore@v4
@@ -268,6 +272,7 @@ jobs:
             ### Patches applied
             - `0007-vesa-dsc-bpp.patch` — VESA DisplayID DSC BPP parser + QP/RC fixes
             - `bigscreen-beyond-edid.patch` — EDID non-desktop quirk (BIG/0x1234 + 0x5095)
+            - `amdgpu-dsc-pps-debugfs.patch` — read-only DSC PPS debugfs observability for Honey lab proof work
             - `cve-2026-31431-algif-aead.patch` — applied automatically for vulnerable 6.19.x bases
             - `dirtyfrag-esp-shared-frag.patch` — applied automatically for CVE-2026-43284 Dirty Frag ESP-affected bases
             - `dirtyfrag-rxrpc-linearize.patch` — applied automatically for reserved CVE-2026-43500 Dirty Frag RxRPC-affected bases

xr/patches/README.md

@@ -8,10 +8,14 @@ Current carry classification:
 
 - `0007-vesa-dsc-bpp.patch`: carry with partial upstream overlap; upstream has AMD DSC passthrough plumbing, but this tree still carries the DisplayID/VESA DSC fixed-BPP parser and DRM connector/mode propagation path. Split that parser/connector path from local QP/RC offset adjustments before submission.
 - `bigscreen-beyond-edid.patch`: upstream candidate for the Bigscreen Beyond non-desktop quirk. Keep the release carry separate from the upstream submission route; the current carry is GNU-patch usable but must be regenerated before v1 submission.
+- `amdgpu-dsc-pps-debugfs.patch`: local Honey lab diagnostic carry. It adds a read-only connector debugfs file for the packed DSC PPS cached by AMD DC; treat this as observability for black-screen proof work, not as a product fix or upstream-ready behavior change.
 
 Detailed split map:
 
 - [`0007-vesa-dsc-bpp.map.md`](0007-vesa-dsc-bpp.map.md)
 - [`bigscreen-beyond-edid.route.md`](bigscreen-beyond-edid.route.md)
 
 The build and release workflows should source patches from here rather than another repo.
+Run `xr/scripts/check-rpm-patch-wiring.sh` after changing `series` or
+`xr/specs/kernel-xr.spec`; it verifies that each carry patch is declared and
+applied by the RPM prep path.

xr/patches/amdgpu-dsc-pps-debugfs.patch

@@ -0,0 +1,98 @@
+From: Jess Sullivan <jess@jesssullivan.dev>
+Subject: [PATCH] drm/amd/display: expose packed DSC PPS in connector debugfs
+
+Bigscreen Beyond black-screen diagnosis needs byte-level proof of the DSC
+Picture Parameter Set sent to the sink. AMD DC already caches the packed
+128-byte PPS in dc_stream_state.dsc_packed_pps when DSC is programmed.
+amdgpu connector debugfs currently exposes only scalar DSC state such as
+BPP, slice geometry, and chunk size.
+
+Add dsc_pic_parameter_set as a read-only connector debugfs file. It dumps
+the cached packed PPS as hex bytes. This does not retrain the link,
+reprogram DSC, or mutate stream state; it only exposes the exact PPS
+payload already generated by the driver.
+
+Signed-off-by: Jess Sullivan <jess@jesssullivan.dev>
+---
+ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 61 ++++++++++++++++++++
+ 1 file changed, 61 insertions(+)
+
+diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+index 000000000000..111111111111 100644
+--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+@@ -2268,6 +2268,66 @@ static ssize_t dp_dsc_bits_per_pixel_write(struct file *f, const char __user *bu
+ 	return size;
+ }
+
++/* Read the packed 128-byte DSC PPS payload cached on the current stream. */
++static ssize_t dp_dsc_pic_parameter_set_read(struct file *f, char __user *buf,
++					     size_t size, loff_t *pos)
++{
++	struct amdgpu_dm_connector *aconnector = file_inode(f)->i_private;
++	struct dc_state *current_state;
++	struct pipe_ctx *pipe_ctx = NULL;
++	const u8 *pps;
++	size_t pps_size;
++	size_t rd_buf_size;
++	char *rd_buf;
++	ssize_t result;
++	size_t i;
++	int pipe_idx;
++	int len = 0;
++
++	if (!aconnector->dc_link ||
++	    !aconnector->dc_link->dc ||
++	    !aconnector->dc_link->dc->current_state)
++		return -ENODEV;
++
++	current_state = aconnector->dc_link->dc->current_state;
++
++	for (pipe_idx = 0; pipe_idx < MAX_PIPES; pipe_idx++) {
++		pipe_ctx = &current_state->res_ctx.pipe_ctx[pipe_idx];
++		if (pipe_ctx->stream &&
++		    pipe_ctx->stream->link == aconnector->dc_link &&
++		    pipe_ctx->stream->sink &&
++		    pipe_ctx->stream->sink == aconnector->dc_sink)
++			break;
++	}
++
++	if (pipe_idx == MAX_PIPES || !pipe_ctx || !pipe_ctx->stream)
++		return -ENODEV;
++
++	pps = pipe_ctx->stream->dsc_packed_pps;
++	pps_size = sizeof(pipe_ctx->stream->dsc_packed_pps);
++	rd_buf_size = pps_size * 3 + 1;
++
++	rd_buf = kcalloc(rd_buf_size, sizeof(char), GFP_KERNEL);
++	if (!rd_buf)
++		return -ENOMEM;
++
++	for (i = 0; i < pps_size; i++) {
++		len += scnprintf(rd_buf + len, rd_buf_size - len,
++				 "%02x%c", pps[i],
++				 i + 1 == pps_size ? '\n' : ' ');
++	}
++
++	result = simple_read_from_buffer(buf, size, pos, rd_buf, len);
++	kfree(rd_buf);
++	return result;
++}
++
++static const struct file_operations dp_dsc_pic_parameter_set_debugfs_fops = {
++	.owner = THIS_MODULE,
++	.read = dp_dsc_pic_parameter_set_read,
++	.llseek = default_llseek
++};
++
+ /* function: read DSC picture width parameter on the connector
+  *
+  * The read function: dp_dsc_pic_width_read
+@@ -3107,6 +3167,7 @@ static const struct {
+ 		{"dsc_slice_width", &dp_dsc_slice_width_debugfs_fops},
+ 		{"dsc_slice_height", &dp_dsc_slice_height_debugfs_fops},
+ 		{"dsc_bits_per_pixel", &dp_dsc_bits_per_pixel_debugfs_fops},
++		{"dsc_pic_parameter_set", &dp_dsc_pic_parameter_set_debugfs_fops},
+ 		{"dsc_pic_width", &dp_dsc_pic_width_debugfs_fops},
+ 		{"dsc_pic_height", &dp_dsc_pic_height_debugfs_fops},
+ 		{"dsc_chunk_size", &dp_dsc_chunk_size_debugfs_fops},

xr/patches/series

@@ -1,2 +1,3 @@
 0007-vesa-dsc-bpp.patch
 bigscreen-beyond-edid.patch
+amdgpu-dsc-pps-debugfs.patch

xr/scripts/build-rpm.sh

@@ -17,6 +17,7 @@ SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 XR_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
 PATCH_DIR="${XR_DIR}/patches"
 SERIES_FILE="${PATCH_DIR}/series"
+PATCH_WIRING_CHECK="${XR_DIR}/scripts/check-rpm-patch-wiring.sh"
 SECURITY_DIR="${XR_DIR}/security"
 SECURITY_CONFIG_CHECK="${XR_DIR}/scripts/check-security-config.sh"
 CVE_2026_31431_PATCH="cve-2026-31431-algif-aead.patch"
@@ -590,6 +591,12 @@ if [[ ! -f "${SERIES_FILE}" ]]; then
     exit 1
 fi
 
+if [[ ! -x "${PATCH_WIRING_CHECK}" ]]; then
+    echo "ERROR: ${PATCH_WIRING_CHECK} not found or not executable."
+    exit 1
+fi
+"${PATCH_WIRING_CHECK}"
+
 mapfile -t PATCHES < <(grep -vE '^[[:space:]]*(#|$)' "${SERIES_FILE}")
 
 if [[ "${#PATCHES[@]}" -eq 0 ]]; then

xr/scripts/check-kernel-carry.sh

@@ -12,6 +12,7 @@ SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 XR_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
 PATCH_DIR="${XR_DIR}/patches"
 SERIES_FILE="${PATCH_DIR}/series"
+PATCH_WIRING_CHECK="${XR_DIR}/scripts/check-rpm-patch-wiring.sh"
 
 usage() {
     cat <<'EOF'
@@ -81,6 +82,12 @@ require_command curl
 require_command patch
 require_command tar
 
+if [[ ! -x "${PATCH_WIRING_CHECK}" ]]; then
+    echo "ERROR: ${PATCH_WIRING_CHECK} not found or not executable." >&2
+    exit 1
+fi
+"${PATCH_WIRING_CHECK}"
+
 if [[ -z "${WORK_DIR}" ]]; then
     WORK_DIR="${TMPDIR:-/tmp}/linux-xr-carry-${KERNEL_VERSION}${RT_VERSION:+-${RT_VERSION}}"
 fi

xr/scripts/check-rpm-patch-wiring.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+# Verify that every XR carry patch listed in series is wired into kernel-xr.spec.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+XR_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
+PATCH_DIR="${XR_DIR}/patches"
+SERIES_FILE="${PATCH_DIR}/series"
+SPEC_FILE="${XR_DIR}/specs/kernel-xr.spec"
+
+usage() {
+    cat <<'EOF'
+Usage: check-rpm-patch-wiring.sh
+
+Checks that every non-comment entry in xr/patches/series:
+  1. exists in xr/patches/
+  2. has a PatchN declaration in xr/specs/kernel-xr.spec
+  3. is applied in %prep by either %patch -PN or an explicit patch command
+
+This is a static guard only; use check-kernel-carry.sh for kernel tarball
+application checks.
+EOF
+}
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --help|-h)
+            usage
+            exit 0
+            ;;
+        *)
+            echo "Unknown option: $1" >&2
+            usage >&2
+            exit 1
+            ;;
+    esac
+done
+
+if [[ ! -f "${SERIES_FILE}" ]]; then
+    echo "ERROR: ${SERIES_FILE} not found." >&2
+    exit 1
+fi
+
+if [[ ! -f "${SPEC_FILE}" ]]; then
+    echo "ERROR: ${SPEC_FILE} not found." >&2
+    exit 1
+fi
+
+status=0
+
+while IFS= read -r patch_file; do
+    case "${patch_file}" in
+        ""|\#*)
+            continue
+            ;;
+    esac
+
+    if [[ ! -f "${PATCH_DIR}/${patch_file}" ]]; then
+        echo "ERROR: missing carry patch ${PATCH_DIR}/${patch_file}" >&2
+        status=1
+        continue
+    fi
+
+    patch_number="$(
+        awk -v patch="${patch_file}" '
+            $1 ~ /^Patch[0-9]+:/ && $2 == patch {
+                sub(/^Patch/, "", $1)
+                sub(/:$/, "", $1)
+                print $1
+                exit
+            }
+        ' "${SPEC_FILE}"
+    )"
+
+    if [[ -z "${patch_number}" ]]; then
+        echo "ERROR: ${patch_file} is in series but has no PatchN declaration in ${SPEC_FILE}." >&2
+        status=1
+        continue
+    fi
+
+    if grep -Eq "%patch[[:space:]]+-P${patch_number}([[:space:]]|$)" "${SPEC_FILE}" ||
+        grep -Fq "_sourcedir}/${patch_file}" "${SPEC_FILE}"; then
+        echo "OK: ${patch_file} -> Patch${patch_number}"
+    else
+        echo "ERROR: ${patch_file} is Patch${patch_number} but is not applied in %prep." >&2
+        status=1
+    fi
+done < "${SERIES_FILE}"
+
+exit "${status}"

xr/source-sync.md

@@ -51,6 +51,9 @@ macOS case-insensitive checkouts for Linux source truth.
 Required checks before moving build defaults or release tags:
 
 ```bash
+# Fast static guard after changing xr/patches/series or kernel-xr.spec:
+./xr/scripts/check-rpm-patch-wiring.sh
+
 # Discover current maintained candidates and optionally run bounded preflights:
 ./xr/scripts/triage-upstream-targets.sh
 ./xr/scripts/triage-upstream-targets.sh --run-preflight

xr/specs/kernel-xr.spec

@@ -42,6 +42,7 @@ Source2:        check-security-config.sh
 # XR patches (fetched by build-rpm.sh into SOURCES/)
 Patch0:         0007-vesa-dsc-bpp.patch
 Patch1:         bigscreen-beyond-edid.patch
+Patch20:        amdgpu-dsc-pps-debugfs.patch
 %if 0%{?apply_cve_2026_31431_patch}
 Patch2:         cve-2026-31431-algif-aead.patch
 %endif
@@ -85,6 +86,7 @@ on AMD GPUs (RDNA2+). Includes:
 - EDID non-desktop quirk for Beyond (BIG/0x1234)
 - DSC QP table corrections for 8bpc 4:4:4 at 8 BPP
 - RC offset fix for ofs[11] in get_ofs_set() CM_444/CM_RGB
+- Read-only DSC PPS debugfs observability for Honey lab proof work
 %if 0%{?apply_cve_2026_31431_patch}
 - CVE-2026-31431 algif_aead backport
 %endif
@@ -144,6 +146,9 @@ patch -p1 < %{_sourcedir}/patch-%{rt_version}.patch
 # EDID non-desktop quirk for Beyond (fuzz needed: context shifted by DSC patch)
 patch -p1 --fuzz=3 < %{_sourcedir}/bigscreen-beyond-edid.patch
 
+# Honey lab diagnostic: expose packed DSC PPS through connector debugfs.
+%patch -P20 -p1
+
 # Apply base config from honey server
 cp %{SOURCE1} .config