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) --- drivers/comedi/range.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 drivers/comedi/range.c (limited to 'drivers/comedi/range.c') diff --git a/drivers/comedi/range.c b/drivers/comedi/range.c new file mode 100644 index 000000000..5b8f66236 --- /dev/null +++ b/drivers/comedi/range.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * comedi/range.c + * comedi routines for voltage ranges + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1997-8 David A. Schleef + */ + +#include +#include +#include "comedi_internal.h" + +const struct comedi_lrange range_bipolar10 = { 1, {BIP_RANGE(10)} }; +EXPORT_SYMBOL_GPL(range_bipolar10); +const struct comedi_lrange range_bipolar5 = { 1, {BIP_RANGE(5)} }; +EXPORT_SYMBOL_GPL(range_bipolar5); +const struct comedi_lrange range_bipolar2_5 = { 1, {BIP_RANGE(2.5)} }; +EXPORT_SYMBOL_GPL(range_bipolar2_5); +const struct comedi_lrange range_unipolar10 = { 1, {UNI_RANGE(10)} }; +EXPORT_SYMBOL_GPL(range_unipolar10); +const struct comedi_lrange range_unipolar5 = { 1, {UNI_RANGE(5)} }; +EXPORT_SYMBOL_GPL(range_unipolar5); +const struct comedi_lrange range_unipolar2_5 = { 1, {UNI_RANGE(2.5)} }; +EXPORT_SYMBOL_GPL(range_unipolar2_5); +const struct comedi_lrange range_0_20mA = { 1, {RANGE_mA(0, 20)} }; +EXPORT_SYMBOL_GPL(range_0_20mA); +const struct comedi_lrange range_4_20mA = { 1, {RANGE_mA(4, 20)} }; +EXPORT_SYMBOL_GPL(range_4_20mA); +const struct comedi_lrange range_0_32mA = { 1, {RANGE_mA(0, 32)} }; +EXPORT_SYMBOL_GPL(range_0_32mA); +const struct comedi_lrange range_unknown = { 1, {{0, 1000000, UNIT_none} } }; +EXPORT_SYMBOL_GPL(range_unknown); + +/* + * COMEDI_RANGEINFO ioctl + * range information + * + * arg: + * pointer to comedi_rangeinfo structure + * + * reads: + * comedi_rangeinfo structure + * + * writes: + * array of comedi_krange structures to rangeinfo->range_ptr pointer + */ +int do_rangeinfo_ioctl(struct comedi_device *dev, + struct comedi_rangeinfo *it) +{ + int subd, chan; + const struct comedi_lrange *lr; + struct comedi_subdevice *s; + + subd = (it->range_type >> 24) & 0xff; + chan = (it->range_type >> 16) & 0xff; + + if (!dev->attached) + return -EINVAL; + if (subd >= dev->n_subdevices) + return -EINVAL; + s = &dev->subdevices[subd]; + if (s->range_table) { + lr = s->range_table; + } else if (s->range_table_list) { + if (chan >= s->n_chan) + return -EINVAL; + lr = s->range_table_list[chan]; + } else { + return -EINVAL; + } + + if (RANGE_LENGTH(it->range_type) != lr->length) { + dev_dbg(dev->class_dev, + "wrong length %d should be %d (0x%08x)\n", + RANGE_LENGTH(it->range_type), + lr->length, it->range_type); + return -EINVAL; + } + + if (copy_to_user(it->range_ptr, lr->range, + sizeof(struct comedi_krange) * lr->length)) + return -EFAULT; + + return 0; +} + +/** + * comedi_check_chanlist() - Validate each element in a chanlist. + * @s: comedi_subdevice struct + * @n: number of elements in the chanlist + * @chanlist: the chanlist to validate + * + * Each element consists of a channel number, a range index, an analog + * reference type and some flags, all packed into an unsigned int. + * + * This checks that the channel number and range index are supported by + * the comedi subdevice. It does not check whether the analog reference + * type and the flags are supported. Drivers that care should check those + * themselves. + * + * Return: %0 if all @chanlist elements are valid (success), + * %-EINVAL if one or more elements are invalid. + */ +int comedi_check_chanlist(struct comedi_subdevice *s, int n, + unsigned int *chanlist) +{ + struct comedi_device *dev = s->device; + unsigned int chanspec; + int chan, range_len, i; + + for (i = 0; i < n; i++) { + chanspec = chanlist[i]; + chan = CR_CHAN(chanspec); + if (s->range_table) + range_len = s->range_table->length; + else if (s->range_table_list && chan < s->n_chan) + range_len = s->range_table_list[chan]->length; + else + range_len = 0; + if (chan >= s->n_chan || + CR_RANGE(chanspec) >= range_len) { + dev_warn(dev->class_dev, + "bad chanlist[%d]=0x%08x chan=%d range length=%d\n", + i, chanspec, chan, range_len); + return -EINVAL; + } + } + return 0; +} +EXPORT_SYMBOL_GPL(comedi_check_chanlist); -- cgit v1.3.1