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/mfd/vx855.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 drivers/mfd/vx855.c (limited to 'drivers/mfd/vx855.c') diff --git a/drivers/mfd/vx855.c b/drivers/mfd/vx855.c new file mode 100644 index 000000000..985f81c17 --- /dev/null +++ b/drivers/mfd/vx855.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Linux multi-function-device driver (MFD) for the integrated peripherals + * of the VIA VX855 chipset + * + * Copyright (C) 2009 VIA Technologies, Inc. + * Copyright (C) 2010 One Laptop per Child + * Author: Harald Welte + * All rights reserved. + */ + +#include +#include +#include +#include +#include +#include + +/* offset into pci config space indicating the 16bit register containing + * the power management IO space base */ +#define VX855_CFG_PMIO_OFFSET 0x88 + +/* ACPI I/O Space registers */ +#define VX855_PMIO_ACPI 0x00 +#define VX855_PMIO_ACPI_LEN 0x0b + +/* Processor Power Management */ +#define VX855_PMIO_PPM 0x10 +#define VX855_PMIO_PPM_LEN 0x08 + +/* General Purpose Power Management */ +#define VX855_PMIO_GPPM 0x20 +#define VX855_PMIO_R_GPI 0x48 +#define VX855_PMIO_R_GPO 0x4c +#define VX855_PMIO_GPPM_LEN 0x33 + +#define VSPIC_MMIO_SIZE 0x1000 + +static struct resource vx855_gpio_resources[] = { + { + .flags = IORESOURCE_IO, + }, + { + .flags = IORESOURCE_IO, + }, +}; + +static const struct mfd_cell vx855_cells[] = { + { + .name = "vx855_gpio", + .num_resources = ARRAY_SIZE(vx855_gpio_resources), + .resources = vx855_gpio_resources, + + /* we must ignore resource conflicts, for reasons outlined in + * the vx855_gpio driver */ + .ignore_resource_conflicts = true, + }, +}; + +static int vx855_probe(struct pci_dev *pdev, + const struct pci_device_id *id) +{ + int ret; + u16 gpio_io_offset; + + ret = pci_enable_device(pdev); + if (ret) + return -ENODEV; + + pci_read_config_word(pdev, VX855_CFG_PMIO_OFFSET, &gpio_io_offset); + if (!gpio_io_offset) { + dev_warn(&pdev->dev, + "BIOS did not assign PMIO base offset?!?\n"); + ret = -ENODEV; + goto out; + } + + /* mask out the lowest seven bits, as they are always zero, but + * hardware returns them as 0x01 */ + gpio_io_offset &= 0xff80; + + /* As the region identified here includes many non-GPIO things, we + * only work with the specific registers that concern us. */ + vx855_gpio_resources[0].start = gpio_io_offset + VX855_PMIO_R_GPI; + vx855_gpio_resources[0].end = vx855_gpio_resources[0].start + 3; + vx855_gpio_resources[1].start = gpio_io_offset + VX855_PMIO_R_GPO; + vx855_gpio_resources[1].end = vx855_gpio_resources[1].start + 3; + + ret = mfd_add_devices(&pdev->dev, -1, vx855_cells, ARRAY_SIZE(vx855_cells), + NULL, 0, NULL); + + /* we always return -ENODEV here in order to enable other + * drivers like old, not-yet-platform_device ported i2c-viapro */ + return -ENODEV; +out: + pci_disable_device(pdev); + return ret; +} + +static void vx855_remove(struct pci_dev *pdev) +{ + mfd_remove_devices(&pdev->dev); + pci_disable_device(pdev); +} + +static const struct pci_device_id vx855_pci_tbl[] = { + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) }, + { 0, } +}; +MODULE_DEVICE_TABLE(pci, vx855_pci_tbl); + +static struct pci_driver vx855_pci_driver = { + .name = "vx855", + .id_table = vx855_pci_tbl, + .probe = vx855_probe, + .remove = vx855_remove, +}; + +module_pci_driver(vx855_pci_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte "); +MODULE_DESCRIPTION("Driver for the VIA VX855 chipset"); -- cgit v1.3.1