From 106b4a2a78b2a2f14885604891957b84bba502db Mon Sep 17 00:00:00 2001 From: Adrian Betschart Date: Fri, 11 Sep 2026 17:13:14 +0200 Subject: drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validation amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and uses the first encoding that validates. YCbCr 4:4:4 is listed before RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the "color format" property is left at AUTO, even though RGB fits the same link. That contradicts the documented AUTO behaviour for HDMI in enum drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when the bandwidth is not available or the mode is 4:2:0-only), which the amdgpu implementation of the property also describes. It also leaves the "Broadcast RGB" property without effect on such sinks, since the quantization range it selects only applies to RGB output. Try RGB first. The mask still holds every encoding the sink supports, so a mode that cannot carry RGB falls back exactly as before. For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI sink that advertised it. Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation") Suggested-by: Adolfo Rodrigues Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart Reviewed-by: Fangzhi Zuo Tested-by: Adolfo Rodrigues Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7) --- scripts/decodecode | 251 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 251 insertions(+) create mode 100755 scripts/decodecode (limited to 'scripts/decodecode') diff --git a/scripts/decodecode b/scripts/decodecode new file mode 100755 index 000000000..01d25dc11 --- /dev/null +++ b/scripts/decodecode @@ -0,0 +1,251 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Disassemble the Code: line in Linux oopses +# usage: decodecode < oops.file +# +# options: set env. variable AFLAGS=options to pass options to "as"; +# e.g., to decode an i386 oops on an x86_64 system, use: +# AFLAGS=--32 decodecode < 386.oops +# PC=hex - the PC (program counter) the oops points to + +faultlinenum=1 + +cleanup() { + rm -f $T $T.s $T.o $T.oo $T.aa $T.dis +} + +die() { + echo "$@" + exit 1 +} + +trap cleanup EXIT + +T=`mktemp` || die "cannot create temp file" +code= +cont= + +while read i ; do + +case "$i" in +*Code:*) + code=$i + cont=yes + ;; +*) + [ -n "$cont" ] && { + xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')" + if [ -n "$xdump" ]; then + code="$code $xdump" + else + cont= + fi + } + ;; +esac + +done + +if [ -z "$code" ]; then + rm $T + die "Code line not found" +fi + +echo $code +code=`echo $code | sed -e 's/.*Code: //'` + +width=`expr index "$code" ' '` +width=$((($width-1)/2)) +case $width in +1) type=byte ;; +2) type=2byte ;; +4) type=4byte ;; +esac + +if [ -z "$ARCH" ]; then + case `uname -m` in + aarch64*) ARCH=arm64 ;; + arm*) ARCH=arm ;; + loongarch*) ARCH=loongarch ;; + esac +fi + +# Params: (tmp_file, pc_sub) +disas() { + t=$1 + pc_sub=$2 + + ${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1 + + if [ "$ARCH" = "arm" ]; then + if [ $width -eq 2 ]; then + OBJDUMPFLAGS="-M force-thumb" + fi + + ${CROSS_COMPILE}strip $t.o + fi + + if [ "$ARCH" = "arm64" ]; then + if [ $width -eq 4 ]; then + type=inst + fi + + ${CROSS_COMPILE}strip $t.o + fi + + if [ "$ARCH" = "riscv" ]; then + OBJDUMPFLAGS="-M no-aliases --section=.text -D" + ${CROSS_COMPILE}strip $t.o + fi + + if [ "$ARCH" = "loongarch" ]; then + ${CROSS_COMPILE}strip $t.o + fi + + if [ $pc_sub -ne 0 ]; then + if [ $PC ]; then + adj_vma=$(( $PC - $pc_sub )) + OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma" + fi + fi + + ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \ + grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1 +} + +# Match the maximum number of opcode bytes from @op_bytes contained within +# @opline +# +# Params: +# @op_bytes: The string of bytes from the Code: line +# @opline: The disassembled line coming from objdump +# +# Returns: +# The max number of opcode bytes from the beginning of @op_bytes which match +# the opcode bytes in the objdump line. +get_substr_opcode_bytes_num() +{ + local op_bytes=$1 + local opline=$2 + + local retval=0 + substr="" + + for opc in $op_bytes; + do + substr+="$opc" + + opcode="$substr" + if [ "$ARCH" = "riscv" ]; then + opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n') + fi + + # return if opcode bytes do not match @opline anymore + if ! echo $opline | grep -q "$opcode"; + then + break + fi + + # add trailing space + substr+=" " + retval=$((retval+1)) + done + + return $retval +} + +# Return the line number in objdump output to where the IP marker in the Code: +# line points to +# +# Params: +# @all_code: code in bytes without the marker +# @dis_file: disassembled file +# @ip_byte: The byte to which the IP points to +get_faultlinenum() +{ + local all_code="$1" + local dis_file="$2" + + # num bytes including IP byte + local num_bytes_ip=$(( $3 + 1 * $width )) + + # Add the two header lines (we're counting from 1). + local retval=3 + + # remove marker + all_code=$(echo $all_code | sed -e 's/[<>()]//g') + + while read line + do + get_substr_opcode_bytes_num "$all_code" "$line" + ate_opcodes=$? + + if ! (( $ate_opcodes )); then + continue + fi + + num_bytes_ip=$((num_bytes_ip - ($ate_opcodes * $width) )) + if (( $num_bytes_ip <= 0 )); then + break + fi + + # Delete matched opcode bytes from all_code. For that, compute + # how many chars those opcodes are represented by and include + # trailing space. + # + # a byte is 2 chars, ate_opcodes is also the number of trailing + # spaces + del_chars=$(( ($ate_opcodes * $width * 2) + $ate_opcodes )) + + all_code=$(echo $all_code | sed -e "s!^.\{$del_chars\}!!") + + let "retval+=1" + + done < $dis_file + + return $retval +} + +marker=`expr index "$code" "\<"` +if [ $marker -eq 0 ]; then + marker=`expr index "$code" "\("` +fi + +touch $T.oo +if [ $marker -ne 0 ]; then + # How many bytes to subtract from the program counter + # in order to get to the beginning virtual address of the + # Code: + pc_sub=$(( (($marker - 1) / (2 * $width + 1)) * $width )) + echo All code >> $T.oo + echo ======== >> $T.oo + beforemark=`echo "$code"` + echo -n " .$type 0x" > $T.s + + echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s + + disas $T $pc_sub + + cat $T.dis >> $T.oo + + get_faultlinenum "$code" "$T.dis" $pc_sub + faultlinenum=$? + + # and fix code at-and-after marker + code=`echo "$code" | cut -c$((${marker} + 1))-` + + rm -f $T.o $T.s $T.dis +fi + +echo Code starting with the faulting instruction > $T.aa +echo =========================================== >> $T.aa +code=`echo $code | sed -e 's/\r//;s/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'` +echo -n " .$type 0x" > $T.s +echo $code >> $T.s +disas $T 0 +cat $T.dis >> $T.aa + +cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/" +echo +cat $T.aa +cleanup -- cgit v1.3.1