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) --- lib/test_dynamic_debug.c | 166 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 lib/test_dynamic_debug.c (limited to 'lib/test_dynamic_debug.c') diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c new file mode 100644 index 000000000..77c2a669b --- /dev/null +++ b/lib/test_dynamic_debug.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel module for testing dynamic_debug + * + * Authors: + * Jim Cromie + */ + +#define pr_fmt(fmt) "test_dd: " fmt + +#include + +/* run tests by reading or writing sysfs node: do_prints */ + +static void do_prints(void); /* device under test */ +static int param_set_do_prints(const char *instr, const struct kernel_param *kp) +{ + do_prints(); + return 0; +} +static int param_get_do_prints(char *buffer, const struct kernel_param *kp) +{ + do_prints(); + return scnprintf(buffer, PAGE_SIZE, "did do_prints\n"); +} +static const struct kernel_param_ops param_ops_do_prints = { + .set = param_set_do_prints, + .get = param_get_do_prints, +}; +module_param_cb(do_prints, ¶m_ops_do_prints, NULL, 0600); + +/* + * Using the CLASSMAP api: + * - classmaps must have corresponding enum + * - enum symbols must match/correlate with class-name strings in the map. + * - base must equal enum's 1st value + * - multiple maps must set their base to share the 0-30 class_id space !! + * (build-bug-on tips welcome) + * Additionally, here: + * - tie together sysname, mapname, bitsname, flagsname + */ +#define DD_SYS_WRAP(_model, _flags) \ + static unsigned long bits_##_model; \ + static struct ddebug_class_param _flags##_model = { \ + .bits = &bits_##_model, \ + .flags = #_flags, \ + .map = &map_##_model, \ + }; \ + module_param_cb(_flags##_##_model, ¶m_ops_dyndbg_classes, &_flags##_model, 0600) + +/* numeric input, independent bits */ +enum cat_disjoint_bits { + D2_CORE = 0, + D2_DRIVER, + D2_KMS, + D2_PRIME, + D2_ATOMIC, + D2_VBL, + D2_STATE, + D2_LEASE, + D2_DP, + D2_DRMRES }; +DECLARE_DYNDBG_CLASSMAP(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, 0, + "D2_CORE", + "D2_DRIVER", + "D2_KMS", + "D2_PRIME", + "D2_ATOMIC", + "D2_VBL", + "D2_STATE", + "D2_LEASE", + "D2_DP", + "D2_DRMRES"); +DD_SYS_WRAP(disjoint_bits, p); +DD_SYS_WRAP(disjoint_bits, T); + +/* symbolic input, independent bits */ +enum cat_disjoint_names { LOW = 11, MID, HI }; +DECLARE_DYNDBG_CLASSMAP(map_disjoint_names, DD_CLASS_TYPE_DISJOINT_NAMES, 10, + "LOW", "MID", "HI"); +DD_SYS_WRAP(disjoint_names, p); +DD_SYS_WRAP(disjoint_names, T); + +/* numeric verbosity, V2 > V1 related */ +enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 }; +DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14, + "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7"); +DD_SYS_WRAP(level_num, p); +DD_SYS_WRAP(level_num, T); + +/* symbolic verbosity */ +enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 }; +DECLARE_DYNDBG_CLASSMAP(map_level_names, DD_CLASS_TYPE_LEVEL_NAMES, 22, + "L0", "L1", "L2", "L3", "L4", "L5", "L6", "L7"); +DD_SYS_WRAP(level_names, p); +DD_SYS_WRAP(level_names, T); + +/* stand-in for all pr_debug etc */ +#define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n") + +static void do_cats(void) +{ + pr_debug("doing categories\n"); + + prdbg(LOW); + prdbg(MID); + prdbg(HI); + + prdbg(D2_CORE); + prdbg(D2_DRIVER); + prdbg(D2_KMS); + prdbg(D2_PRIME); + prdbg(D2_ATOMIC); + prdbg(D2_VBL); + prdbg(D2_STATE); + prdbg(D2_LEASE); + prdbg(D2_DP); + prdbg(D2_DRMRES); +} + +static void do_levels(void) +{ + pr_debug("doing levels\n"); + + prdbg(V1); + prdbg(V2); + prdbg(V3); + prdbg(V4); + prdbg(V5); + prdbg(V6); + prdbg(V7); + + prdbg(L1); + prdbg(L2); + prdbg(L3); + prdbg(L4); + prdbg(L5); + prdbg(L6); + prdbg(L7); +} + +static void do_prints(void) +{ + do_cats(); + do_levels(); +} + +static int __init test_dynamic_debug_init(void) +{ + pr_debug("init start\n"); + do_prints(); + pr_debug("init done\n"); + return 0; +} + +static void __exit test_dynamic_debug_exit(void) +{ + pr_debug("exited\n"); +} + +module_init(test_dynamic_debug_init); +module_exit(test_dynamic_debug_exit); + +MODULE_AUTHOR("Jim Cromie "); +MODULE_DESCRIPTION("Kernel module for testing dynamic_debug"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1