Commit 7c395ea521e6 made Bluetooth stop working on the MacBookPro16,1. I
believe this also affected the iMac20,1. The patch below introduces a quirk
disabling Read LE Min/Max Tx Power for affected computers, based off the brcm
chip
id 150.
I think there are a couple of issues with this patch that I don't have the
knowledge to resolve:
1. I don't know how accurate the description of the quirk is, I based it off
the commit message of 7c395ea521e6m, however I don't understand much about
how Bluetooth works. Other Bluetooth quirks also have explanations as to
why they are needed, I don't know why this quirk is needed (is it that
these chips incorrectly say they support read le minmax tx power? I just
don't know).
2. It may be a bug in the min max le tx power code that could be fixed instead
of disabling it for the affected devices.
I haven't had much success in figuring out exactly why reading le minmax tx
power stops Bluetooth from working. I have noticed that these lines are not
present in dmesg when Bluetooth is not working due to this issue:
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver 1.11
I have also added some logging around the changes in 7c395ea521e6, the two
patches (one with bt working one without) I tried and their associated dmesgs
are here https://gist.github.com/Redecorating/8330bb58a7cb8730be3956058ba4599f
Regards,
Orlando Chamberlain
---
drivers/bluetooth/btbcm.c | 4 ++++
include/net/bluetooth/hci.h | 9 +++++++++
net/bluetooth/hci_core.c | 3 ++-
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/bluetooth/btbcm.c b/drivers/bluetooth/btbcm.c
index e4182acee488..4ecc50d93107 100644
--- a/drivers/bluetooth/btbcm.c
+++ b/drivers/bluetooth/btbcm.c
@@ -353,6 +353,10 @@ static int btbcm_read_info(struct hci_dev *hdev)
return PTR_ERR(skb);
bt_dev_info(hdev, "BCM: chip id %u", skb->data[1]);
+
+ if (skb->data[1] == 150)
+ set_bit(HCI_QUIRK_BROKEN_READ_TRANSMIT_POWER, &hdev->quirks);
+
kfree_skb(skb);
/* Read Controller Features */
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index b80415011dcd..9ce46cb8564d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -246,6 +246,15 @@ enum {
* HCI after resume.
*/
HCI_QUIRK_NO_SUSPEND_NOTIFIER,
+
+ /*
+ * When this quirk is set, LE tx power is not queried on startup
+ * and the min/max tx power values default to HCI_TX_POWER_INVALID.
+ *
+ * This quirk can be set before hci_register_dev is called or
+ * during the hdev->setup vendor callback.
+ */
+ HCI_QUIRK_BROKEN_READ_TRANSMIT_POWER,
};
/* HCI device flags */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 8a47a3017d61..9a23fe7c8d67 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -742,7 +742,8 @@ static int hci_init3_req(struct hci_request *req, unsigned long opt)
hci_req_add(req, HCI_OP_LE_READ_ADV_TX_POWER, 0, NULL);
}
- if (hdev->commands[38] & 0x80) {
+ if (hdev->commands[38] & 0x80 &&
+ !test_bit(HCI_QUIRK_BROKEN_READ_TRANSMIT_POWER, &hdev->quirks)) {
/* Read LE Min/Max Tx Power*/
hci_req_add(req, HCI_OP_LE_READ_TRANSMIT_POWER,
0, NULL);
--
2.33.0