On 13-Jan-2022, at 4:17 PM, gregkh@linuxfoundation.org wrote:

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 801b4c027b44a185292007d3cf7513999d644723 Mon Sep 17 00:00:00 2001 From: Aditya Garg gargaditya08@live.com Date: Thu, 2 Dec 2021 12:42:59 +0000 Subject: [PATCH] Bluetooth: btbcm: disable read tx power for some Macs with the T2 Security chip

From: Aditya Garg gargaditya08@live.com

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@live.com Reported-by: Orlando Chamberlain redecorating@protonmail.com Tested-by: Orlando Chamberlain redecorating@protonmail.com Link: https://lore.kernel.org/r/4970a940-211b-25d6-edab-21a815313954@protonmail.co... Fixes: 7c395ea521e6 ("Bluetooth: Query LE tx power on startup") Cc: stable@vger.kernel.org Signed-off-by: Marcel Holtmann marcel@holtmann.org --- drivers/bluetooth/btbcm.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)

diff --git a/drivers/bluetooth/btbcm.c b/drivers/bluetooth/btbcm.c index e4182acee..07fabaa5a 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; }