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/input/misc/ibm-panel.c | 196 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 196 insertions(+) create mode 100644 drivers/input/misc/ibm-panel.c (limited to 'drivers/input/misc/ibm-panel.c') diff --git a/drivers/input/misc/ibm-panel.c b/drivers/input/misc/ibm-panel.c new file mode 100644 index 000000000..aa48f62d7 --- /dev/null +++ b/drivers/input/misc/ibm-panel.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) IBM Corporation 2020 + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define DEVICE_NAME "ibm-panel" +#define PANEL_KEYCODES_COUNT 3 + +struct ibm_panel { + u8 idx; + u8 command[11]; + u32 keycodes[PANEL_KEYCODES_COUNT]; + spinlock_t lock; /* protects writes to idx and command */ + struct input_dev *input; +}; + +static u8 ibm_panel_calculate_checksum(struct ibm_panel *panel) +{ + u8 chksum; + u16 sum = 0; + unsigned int i; + + for (i = 0; i < sizeof(panel->command) - 1; ++i) { + sum += panel->command[i]; + if (sum & 0xff00) { + sum &= 0xff; + sum++; + } + } + + chksum = sum & 0xff; + chksum = ~chksum; + chksum++; + + return chksum; +} + +static void ibm_panel_process_command(struct ibm_panel *panel) +{ + u8 button; + u8 chksum; + + if (panel->command[0] != 0xff && panel->command[1] != 0xf0) { + dev_dbg(&panel->input->dev, "command invalid: %02x %02x\n", + panel->command[0], panel->command[1]); + return; + } + + chksum = ibm_panel_calculate_checksum(panel); + if (chksum != panel->command[sizeof(panel->command) - 1]) { + dev_dbg(&panel->input->dev, + "command failed checksum: %u != %u\n", chksum, + panel->command[sizeof(panel->command) - 1]); + return; + } + + button = panel->command[2] & 0xf; + if (button < PANEL_KEYCODES_COUNT) { + input_report_key(panel->input, panel->keycodes[button], + !(panel->command[2] & 0x80)); + input_sync(panel->input); + } else { + dev_dbg(&panel->input->dev, "unknown button %u\n", + button); + } +} + +static int ibm_panel_i2c_slave_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct ibm_panel *panel = i2c_get_clientdata(client); + + dev_dbg(&panel->input->dev, "event: %u data: %02x\n", event, *val); + + guard(spinlock_irqsave)(&panel->lock); + + switch (event) { + case I2C_SLAVE_STOP: + if (panel->idx == sizeof(panel->command)) + ibm_panel_process_command(panel); + else + dev_dbg(&panel->input->dev, + "command incorrect size %u\n", panel->idx); + fallthrough; + case I2C_SLAVE_WRITE_REQUESTED: + panel->idx = 0; + break; + case I2C_SLAVE_WRITE_RECEIVED: + if (panel->idx < sizeof(panel->command)) + panel->command[panel->idx++] = *val; + else + /* + * The command is too long and therefore invalid, so set the index + * to it's largest possible value. When a STOP is finally received, + * the command will be rejected upon processing. + */ + panel->idx = U8_MAX; + break; + case I2C_SLAVE_READ_REQUESTED: + case I2C_SLAVE_READ_PROCESSED: + *val = 0xff; + break; + default: + break; + } + + return 0; +} + +static int ibm_panel_probe(struct i2c_client *client) +{ + struct ibm_panel *panel; + int i; + int error; + + panel = devm_kzalloc(&client->dev, sizeof(*panel), GFP_KERNEL); + if (!panel) + return -ENOMEM; + + spin_lock_init(&panel->lock); + + panel->input = devm_input_allocate_device(&client->dev); + if (!panel->input) + return -ENOMEM; + + panel->input->name = client->name; + panel->input->id.bustype = BUS_I2C; + + error = device_property_read_u32_array(&client->dev, + "linux,keycodes", + panel->keycodes, + PANEL_KEYCODES_COUNT); + if (error) { + /* + * Use gamepad buttons as defaults for compatibility with + * existing applications. + */ + panel->keycodes[0] = BTN_NORTH; + panel->keycodes[1] = BTN_SOUTH; + panel->keycodes[2] = BTN_SELECT; + } + + for (i = 0; i < PANEL_KEYCODES_COUNT; ++i) + input_set_capability(panel->input, EV_KEY, panel->keycodes[i]); + + error = input_register_device(panel->input); + if (error) { + dev_err(&client->dev, + "Failed to register input device: %d\n", error); + return error; + } + + i2c_set_clientdata(client, panel); + error = i2c_slave_register(client, ibm_panel_i2c_slave_cb); + if (error) { + dev_err(&client->dev, + "Failed to register as i2c slave: %d\n", error); + return error; + } + + return 0; +} + +static void ibm_panel_remove(struct i2c_client *client) +{ + i2c_slave_unregister(client); +} + +static const struct of_device_id ibm_panel_match[] = { + { .compatible = "ibm,op-panel" }, + { } +}; +MODULE_DEVICE_TABLE(of, ibm_panel_match); + +static struct i2c_driver ibm_panel_driver = { + .driver = { + .name = DEVICE_NAME, + .of_match_table = ibm_panel_match, + }, + .probe = ibm_panel_probe, + .remove = ibm_panel_remove, +}; +module_i2c_driver(ibm_panel_driver); + +MODULE_AUTHOR("Eddie James "); +MODULE_DESCRIPTION("IBM Operation Panel Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1