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authorAdrian Betschart <adrian.betschart@cinemaone.ch>2026-09-11 17:13:14 +0200
committerAlex Deucher <alexander.deucher@amd.com>2026-10-01 17:18:05 -0400
commit106b4a2a78b2a2f14885604891957b84bba502db (patch)
tree5d40eef2428fb1a4791ab46a4b19091a5910eac2 /drivers/hid/hid-gembird.c
downloadlinux-stable-106b4a2a78b2a2f14885604891957b84bba502db.tar.gz
linux-stable-106b4a2a78b2a2f14885604891957b84bba502db.zip
drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted
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 <adolfotregosa@gmail.com> Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch> Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com> Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)
Diffstat (limited to 'drivers/hid/hid-gembird.c')
-rw-r--r--drivers/hid/hid-gembird.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/drivers/hid/hid-gembird.c b/drivers/hid/hid-gembird.c
new file mode 100644
index 000000000..20a8de766
--- /dev/null
+++ b/drivers/hid/hid-gembird.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HID driver for Gembird Joypad, "PC Game Controller"
+ *
+ * Copyright (c) 2015 Red Hat, Inc
+ * Copyright (c) 2015 Benjamin Tissoires
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define GEMBIRD_START_FAULTY_RDESC 8
+
+static const __u8 gembird_jpd_faulty_rdesc[] = {
+ 0x75, 0x08, /* Report Size (8) */
+ 0x95, 0x05, /* Report Count (5) */
+ 0x15, 0x00, /* Logical Minimum (0) */
+ 0x26, 0xff, 0x00, /* Logical Maximum (255) */
+ 0x35, 0x00, /* Physical Minimum (0) */
+ 0x46, 0xff, 0x00, /* Physical Maximum (255) */
+ 0x09, 0x30, /* Usage (X) */
+ 0x09, 0x31, /* Usage (Y) */
+ 0x09, 0x32, /* Usage (Z) */
+ 0x09, 0x32, /* Usage (Z) */
+ 0x09, 0x35, /* Usage (Rz) */
+ 0x81, 0x02, /* Input (Data,Var,Abs) */
+};
+
+/*
+ * we fix the report descriptor by:
+ * - marking the first Z axis as constant (so it is ignored by HID)
+ * - assign the original second Z to Rx
+ * - assign the original Rz to Ry
+ */
+static const __u8 gembird_jpd_fixed_rdesc[] = {
+ 0x75, 0x08, /* Report Size (8) */
+ 0x95, 0x02, /* Report Count (2) */
+ 0x15, 0x00, /* Logical Minimum (0) */
+ 0x26, 0xff, 0x00, /* Logical Maximum (255) */
+ 0x35, 0x00, /* Physical Minimum (0) */
+ 0x46, 0xff, 0x00, /* Physical Maximum (255) */
+ 0x09, 0x30, /* Usage (X) */
+ 0x09, 0x31, /* Usage (Y) */
+ 0x81, 0x02, /* Input (Data,Var,Abs) */
+ 0x95, 0x01, /* Report Count (1) */
+ 0x09, 0x32, /* Usage (Z) */
+ 0x81, 0x01, /* Input (Cnst,Arr,Abs) */
+ 0x95, 0x02, /* Report Count (2) */
+ 0x09, 0x33, /* Usage (Rx) */
+ 0x09, 0x34, /* Usage (Ry) */
+ 0x81, 0x02, /* Input (Data,Var,Abs) */
+};
+
+static const __u8 *gembird_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+ unsigned int *rsize)
+{
+ __u8 *new_rdesc;
+ /* delta_size is > 0 */
+ size_t delta_size = sizeof(gembird_jpd_fixed_rdesc) -
+ sizeof(gembird_jpd_faulty_rdesc);
+ size_t new_size = *rsize + delta_size;
+
+ if (*rsize >= 31 && !memcmp(&rdesc[GEMBIRD_START_FAULTY_RDESC],
+ gembird_jpd_faulty_rdesc,
+ sizeof(gembird_jpd_faulty_rdesc))) {
+ new_rdesc = devm_kzalloc(&hdev->dev, new_size, GFP_KERNEL);
+ if (new_rdesc == NULL)
+ return rdesc;
+
+ dev_info(&hdev->dev,
+ "fixing Gembird JPD-DualForce 2 report descriptor.\n");
+
+ /* start by copying the end of the rdesc */
+ memcpy(new_rdesc + delta_size, rdesc, *rsize);
+
+ /* add the correct beginning */
+ memcpy(new_rdesc, rdesc, GEMBIRD_START_FAULTY_RDESC);
+
+ /* replace the faulty part with the fixed one */
+ memcpy(new_rdesc + GEMBIRD_START_FAULTY_RDESC,
+ gembird_jpd_fixed_rdesc,
+ sizeof(gembird_jpd_fixed_rdesc));
+
+ *rsize = new_size;
+ rdesc = new_rdesc;
+ }
+
+ return rdesc;
+}
+
+static const struct hid_device_id gembird_devices[] = {
+ { HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
+ USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
+ { }
+};
+MODULE_DEVICE_TABLE(hid, gembird_devices);
+
+static struct hid_driver gembird_driver = {
+ .name = "gembird",
+ .id_table = gembird_devices,
+ .report_fixup = gembird_report_fixup,
+};
+module_hid_driver(gembird_driver);
+
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_DESCRIPTION("HID Gembird joypad driver");
+MODULE_LICENSE("GPL");