[PATCH v9 2/2] btbcm: disable read tx power for affected Macs with the T2 Security chip

[Aditya Garg <gargaditya08@xxxxxxxx>]

From: Aditya Garg <gargaditya08@xxxxxxxx>

Some Macs with the T2 security chip had Bluetooth not working.
To fix it we add DMI based quirks to disable querying of LE Tx power.

Signed-off-by: Aditya Garg <gargaditya08@xxxxxxxx>
Reported-by: Orlando Chamberlain <redecorating@xxxxxxxxxxxxxx>
Tested-by: Orlando Chamberlain <redecorating@xxxxxxxxxxxxxx>
Link:
https://lore.kernel.org/r/4970a940-211b-25d6-edab-21a815313954@xxxxxxxxxxxxxx
Fixes: 7c395ea521e6 ("Bluetooth: Query LE tx power on startup")
Cc: stable@xxxxxxxxxxxxxxx
---
v7 :- Removed unused variable and added Tested-by.
v8 :- No change.
v9 :- Add Cc: stable@xxxxxxxxxxxxxxx
 drivers/bluetooth/btbcm.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/bluetooth/btbcm.c b/drivers/bluetooth/btbcm.c
index e4182acee488c5..07fabaa5aa2979 100644
--- a/drivers/bluetooth/btbcm.c
+++ b/drivers/bluetooth/btbcm.c
@@ -8,6 +8,7 @@
 
 #include <linux/module.h>
 #include <linux/firmware.h>
+#include <linux/dmi.h>
 #include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -343,6 +344,40 @@ static struct sk_buff *btbcm_read_usb_product(struct hci_dev *hdev)
 	return skb;
 }
 
+static const struct dmi_system_id disable_broken_read_transmit_power[] = {
+	{
+		 .matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,1"),
+		},
+	},
+	{
+		 .matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,2"),
+		},
+	},
+	{
+		 .matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,4"),
+		},
+	},
+	{
+		 .matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,1"),
+		},
+	},
+	{
+		 .matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,2"),
+		},
+	},
+	{ }
+};
+
 static int btbcm_read_info(struct hci_dev *hdev)
 {
 	struct sk_buff *skb;
@@ -363,6 +398,10 @@ static int btbcm_read_info(struct hci_dev *hdev)
 	bt_dev_info(hdev, "BCM: features 0x%2.2x", skb->data[1]);
 	kfree_skb(skb);
 
+	/* Read DMI and disable broken Read LE Min/Max Tx Power */
+	if (dmi_first_match(disable_broken_read_transmit_power))
+		set_bit(HCI_QUIRK_BROKEN_READ_TRANSMIT_POWER, &hdev->quirks);
+
 	return 0;
 }