[PATCH v2 RESEND RESEND] Bluetooth: btqcomsmd: Fix command timeout after setting BD address

[PATCH v2 RESEND RESEND] Bluetooth: btqcomsmd: Fix command timeout after setting BD address

[Stephan Gerhold]

On most devices using the btqcomsmd driver (e.g. the DragonBoard 410c
and other devices based on the Qualcomm MSM8916/MSM8909/... SoCs)
the Bluetooth firmware seems to become unresponsive for a while after
setting the BD address. On recent kernel versions (at least 5.17+)
this often causes timeouts for subsequent commands, e.g. the HCI reset
sent by the Bluetooth core during initialization:

    Bluetooth: hci0: Opcode 0x c03 failed: -110

Unfortunately this behavior does not seem to be documented anywhere.
Experimentation suggests that the minimum necessary delay to avoid
the problem is ~150us. However, to be sure add a sleep for > 1ms
in case it is a bit longer on other firmware versions.

Older kernel versions are likely also affected, although perhaps with
slightly different errors or less probability. Side effects can easily
hide the issue in most cases, e.g. unrelated incoming interrupts that
cause the necessary delay.

Fixes: 1511cc750c3d ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
---
Unmodified second resend of the v2 I sent back in June and again in
October, it seems to have been archived again in patchwork. Any kind of
feedback would be much appreciated! :)

I tested this using a script that reboots repeatedly and checks for the
error. With this patch, BT shows up successfully for 100+ consecutive
boots. Without this patch it usually fails after 1-5 boots (or even
always on some boards).

Changes in v2:
  - Clarify commit message: Add affected devices and kernel versions
---
 drivers/bluetooth/btqcomsmd.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btqcomsmd.c b/drivers/bluetooth/btqcomsmd.c
index 2acb719e596f..11c7e04bf394 100644
--- a/drivers/bluetooth/btqcomsmd.c
+++ b/drivers/bluetooth/btqcomsmd.c
@@ -122,6 +122,21 @@ static int btqcomsmd_setup(struct hci_dev *hdev)
 	return 0;
 }
 
+static int btqcomsmd_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
+{
+	int ret;
+
+	ret = qca_set_bdaddr_rome(hdev, bdaddr);
+	if (ret)
+		return ret;
+
+	/* The firmware stops responding for a while after setting the bdaddr,
+	 * causing timeouts for subsequent commands. Sleep a bit to avoid this.
+	 */
+	usleep_range(1000, 10000);
+	return 0;
+}
+
 static int btqcomsmd_probe(struct platform_device *pdev)
 {
 	struct btqcomsmd *btq;
@@ -162,7 +177,7 @@ static int btqcomsmd_probe(struct platform_device *pdev)
 	hdev->close = btqcomsmd_close;
 	hdev->send = btqcomsmd_send;
 	hdev->setup = btqcomsmd_setup;
-	hdev->set_bdaddr = qca_set_bdaddr_rome;
+	hdev->set_bdaddr = btqcomsmd_set_bdaddr;
 
 	ret = hci_register_dev(hdev);
 	if (ret < 0)
-- 
2.30.2

RE: [v2,RESEND,RESEND] Bluetooth: btqcomsmd: Fix command timeout after setting BD address

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2081 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=712703

---Test result---

Test Summary:
CheckPatch                    PASS      0.53 seconds
GitLint                       FAIL      0.52 seconds
SubjectPrefix                 PASS      0.07 seconds
BuildKernel                   PASS      30.81 seconds
CheckAllWarning               PASS      33.48 seconds
CheckSparse                   PASS      37.88 seconds
CheckSmatch                   PASS      106.53 seconds
BuildKernel32                 PASS      29.58 seconds
TestRunnerSetup               PASS      428.64 seconds
TestRunner_l2cap-tester       PASS      15.91 seconds
TestRunner_iso-tester         PASS      16.21 seconds
TestRunner_bnep-tester        PASS      5.44 seconds
TestRunner_mgmt-tester        PASS      107.46 seconds
TestRunner_rfcomm-tester      PASS      8.64 seconds
TestRunner_sco-tester         PASS      7.89 seconds
TestRunner_ioctl-tester       PASS      9.15 seconds
TestRunner_mesh-tester        PASS      6.85 seconds
TestRunner_smp-tester         PASS      7.81 seconds
TestRunner_userchan-tester    PASS      5.70 seconds
IncrementalBuild              PASS      27.79 seconds

Details
##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
[v2,RESEND,RESEND] Bluetooth: btqcomsmd: Fix command timeout after setting BD address

WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
1: T1 Title exceeds max length (85>80): "[v2,RESEND,RESEND] Bluetooth: btqcomsmd: Fix command timeout after setting BD address"


---
Regards,
Linux Bluetooth