[PATCH v3 0/2] Bluetooth: btusb: Fake CSR dongle fixes

[PATCH v3 0/2] Bluetooth: btusb: Fake CSR dongle fixes

[Hans de Goede]

Hi All,

As requested here are my 2 btusb fake CSR dongle fixes as a series again
because the second patch depends on the first patch.

Regards,

Jans

[PATCH v3 1/2] Bluetooth: btusb: Fix detection of some fake CSR controllers with a bcdDevice val of 0x0134

[Hans de Goede]

Commit cde1a8a99287 ("Bluetooth: btusb: Fix and detect most of the
Chinese Bluetooth controllers") made the detection of fake controllers
more generic fixing it for much of the newer fakes / clones.

But this does not work for a fake CSR controller with a bcdDevice
value of 0x0134, which was correctly identified as fake before
this change.

Add an extra check for this special case, checking for a combination
of a bcdDevice value of 0x0134, together with a lmp_subver of 0x0c5c
and a hci_ver of BLUETOOTH_VER_2_0.

The chip inside this fake dongle is marked as with "clockwise cw6629d".

Fixes: cde1a8a99287 ("Bluetooth: btusb: Fix and detect most of the Chinese Bluetooth controllers")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
-Add description of chip inside the fake dongle to the commit message
---
 drivers/bluetooth/btusb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 1005b6e8ff74..ac7fede4f951 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1763,6 +1763,8 @@ static int btusb_setup_bcm92035(struct hci_dev *hdev)
 
 static int btusb_setup_csr(struct hci_dev *hdev)
 {
+	struct btusb_data *data = hci_get_drvdata(hdev);
+	u16 bcdDevice = le16_to_cpu(data->udev->descriptor.bcdDevice);
 	struct hci_rp_read_local_version *rp;
 	struct sk_buff *skb;
 	bool is_fake = false;
@@ -1832,6 +1834,12 @@ static int btusb_setup_csr(struct hci_dev *hdev)
 		 le16_to_cpu(rp->hci_ver) > BLUETOOTH_VER_4_0)
 		is_fake = true;
 
+	/* Other clones which beat all the above checks */
+	else if (bcdDevice == 0x0134 &&
+		 le16_to_cpu(rp->lmp_subver) == 0x0c5c &&
+		 le16_to_cpu(rp->hci_ver) == BLUETOOTH_VER_2_0)
+		is_fake = true;
+
 	if (is_fake) {
 		bt_dev_warn(hdev, "CSR: Unbranded CSR clone detected; adding workarounds...");
 
-- 
2.28.0

[PATCH v3 2/2] Bluetooth: btusb: Add workaround for remote-wakeup issues with Barrot 8041a02 fake CSR controllers

[Hans de Goede]

With the recent btusb change to detect and deal with more fake CSR
controllers, I decided to see if fake CSR controllers with Barrot
8041a02 chips would now work.

After much experimentation I came to the conclusion that it works, if I
have autosuspend enabled initially and then disable it after the device
has suspended at least once. Yes this is very weird, but I've tried many
things, like manually clearing the remote-wakeup feature. Doing a
runtime-resume + runtime suspend is the only way to get the receiver
to actually report received data (and/or pairing info) through its
bulk rx endpoint.

But the funkyness of the bulk-endpoint does not stop there, I mainly
found out about this problem, because with autosuspend enabled
(which usually ensures the suspend at least once condition is met),
the receiver stops reporting received data through its bulk rx endpoint
as soon as autosuspend kicks in. So I initially just disabled
autosuspend, but then the receiver does not work at all.

This was with a fake CSR receiver with a Barrot 8041a02 chip with a
bcdDevice value of 0x8891, a lmp_subver of 0x1012, a hci_rev of 0x0810
and a hci_ver of BLUETOOTH_VER_4_0.

Summarizing this specific fake CSR receiver has the following 2 issues:

1. The bulk rx endpoint will never report any data unless
the device was suspended at least once.

2. They will not wakeup when autosuspended and receiving data on their
bulk rx endpoint from e.g. a keyboard or mouse (IOW remote-wakeup support
is broken for the bulk endpoint).

Add a workaround for 1. which enables runtime-suspend, force-suspends
the hci and then wakes-it up by disabling runtime-suspend again.

Add a workaround for 2. which clears the hci's can_wake flag, this way
the hci will still be autosuspended when it is not open.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v3:
- Add info about which fake CSR chip this happens on to the commit message
  and source code comment
- Only apply the workaround on this specific chip
---
 drivers/bluetooth/btusb.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index ac7fede4f951..236aefaf925c 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1768,6 +1768,7 @@ static int btusb_setup_csr(struct hci_dev *hdev)
 	struct hci_rp_read_local_version *rp;
 	struct sk_buff *skb;
 	bool is_fake = false;
+	int ret;
 
 	BT_DBG("%s", hdev->name);
 
@@ -1856,6 +1857,43 @@ static int btusb_setup_csr(struct hci_dev *hdev)
 		 */
 		clear_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
 		clear_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
+
+		/*
+		 * Special workaround for clones with a Barrot 8041a02 chip,
+		 * these clones are really messed-up:
+		 * 1. Their bulk rx endpoint will never report any data unless
+		 * the device was suspended at least once (yes really).
+		 * 2. They will not wakeup when autosuspended and receiving data
+		 * on their bulk rx endpoint from e.g. a keyboard or mouse
+		 * (IOW remote-wakeup support is broken for the bulk endpoint).
+		 *
+		 * To fix 1. enable runtime-suspend, force-suspend the
+		 * hci and then wake-it up by disabling runtime-suspend.
+		 *
+		 * To fix 2. clear the hci's can_wake flag, this way the hci
+		 * will still be autosuspended when it is not open.
+		 */
+		if (bcdDevice == 0x8891 &&
+		    le16_to_cpu(rp->lmp_subver) == 0x1012 &&
+		    le16_to_cpu(rp->hci_rev) == 0x0810 &&
+		    le16_to_cpu(rp->hci_ver) == BLUETOOTH_VER_4_0) {
+			bt_dev_warn(hdev, "CSR: detected a fake CSR dongle using a Barrot 8041a02 chip, this chip is very buggy and may have issues\n");
+
+			pm_runtime_allow(&data->udev->dev);
+
+			ret = pm_runtime_suspend(&data->udev->dev);
+			if (ret >= 0)
+				msleep(200);
+			else
+				bt_dev_err(hdev, "Failed to suspend the device for Barrot 8041a02 receive-issue workaround\n");
+
+			pm_runtime_forbid(&data->udev->dev);
+
+			device_set_wakeup_capable(&data->udev->dev, false);
+			/* Re-enable autosuspend if this was requested */
+			if (enable_autosuspend)
+				usb_enable_autosuspend(data->udev);
+		}
 	}
 
 	kfree_skb(skb);
-- 
2.28.0

RE: Bluetooth: btusb: Fake CSR dongle fixes

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1120 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=396867

---Test result---

##############################
Test: CheckPatch - PASS

##############################
Test: CheckGitLint - FAIL
Output:
Bluetooth: btusb: Fix detection of some fake CSR controllers with a bcdDevice val of 0x0134
1: T1 Title exceeds max length (91>72): "Bluetooth: btusb: Fix detection of some fake CSR controllers with a bcdDevice val of 0x0134"
17: B1 Line exceeds max length (98>80): "Fixes: cde1a8a99287 ("Bluetooth: btusb: Fix and detect most of the Chinese Bluetooth controllers")"

Bluetooth: btusb: Add workaround for remote-wakeup issues with Barrot 8041a02 fake CSR controllers
1: T1 Title exceeds max length (98>72): "Bluetooth: btusb: Add workaround for remote-wakeup issues with Barrot 8041a02 fake CSR controllers"


##############################
Test: CheckBuildK - PASS



---
Regards,
Linux Bluetooth

Re: [PATCH v3 0/2] Bluetooth: btusb: Fake CSR dongle fixes

[Marcel Holtmann]

Hi Hans,

> As requested here are my 2 btusb fake CSR dongle fixes as a series again
> because the second patch depends on the first patch.

both patches have been applied bluetooth-next tree.

Regards

Marcel