x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 75 insertions, 0 deletions

diff --git a/drivers/hid/hid-evision.c b/drivers/hid/hid-evision.c
new file mode 100644
index 000000000..3e7f43ab8
--- /dev/null
+++ b/drivers/hid/hid-evision.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for EVision devices
+ *  For now, only ignore bogus consumer reports
+ *  sent after the keyboard has been configured
+ *
+ *  Copyright (c) 2022 Philippe Valembois
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static int evision_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	/* mapping only applies to USB_DEVICE_ID_EVISION_ICL01 */
+	if (hdev->product != USB_DEVICE_ID_EVISION_ICL01)
+		return 0;
+
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_CONSUMER)
+		return 0;
+
+	/* Ignore key down event */
+	if ((usage->hid & HID_USAGE) >> 8 == 0x05)
+		return -1;
+	/* Ignore key up event */
+	if ((usage->hid & HID_USAGE) >> 8 == 0x06)
+		return -1;
+
+	switch (usage->hid & HID_USAGE) {
+	/* Ignore configuration saved event */
+	case 0x0401: return -1;
+	/* Ignore reset event */
+	case 0x0402: return -1;
+	}
+	return 0;
+}
+
+#define REP_DSC_SIZE 236
+#define USAGE_MAX_INDEX 59
+
+static const __u8 *evision_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (hdev->product == USB_DEVICE_ID_EV_TELINK_RECEIVER &&
+	    *rsize == REP_DSC_SIZE && rdesc[USAGE_MAX_INDEX] == 0x29 &&
+	    rdesc[USAGE_MAX_INDEX + 1] == 3) {
+		hid_info(hdev, "fixing EVision:TeLink Receiver report descriptor\n");
+		rdesc[USAGE_MAX_INDEX + 1] = 5; // change usage max from 3 to 5
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id evision_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_EVISION, USB_DEVICE_ID_EVISION_ICL01) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_EVISION, USB_DEVICE_ID_EV_TELINK_RECEIVER) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, evision_devices);
+
+static struct hid_driver evision_driver = {
+	.name = "evision",
+	.id_table = evision_devices,
+	.input_mapping = evision_input_mapping,
+	.report_fixup = evision_report_fixup,
+};
+module_hid_driver(evision_driver);
+
+MODULE_DESCRIPTION("HID driver for EVision devices");
+MODULE_LICENSE("GPL");