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Date:   Thu, 13 Jan 2022 15:46:52 +0800
Message-Id: <20220113154626.Bluez.v2.1.Iad485a29772515142eefb1b120d5eb5e101d82f6@changeid>
Mime-Version: 1.0
Subject: [Bluez PATCH v2] device: Fix device can't be scanned for 5 mins after reboot
From:   Archie Pusaka <apusaka@google.com>
To:     linux-bluetooth <linux-bluetooth@vger.kernel.org>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Marcel Holtmann <marcel@holtmann.org>
Cc:     CrosBT Upstreaming <chromeos-bluetooth-upstreaming@chromium.org>,
        Archie Pusaka <apusaka@chromium.org>
Content-Type: text/plain; charset="UTF-8"
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From: Archie Pusaka <apusaka@chromium.org>

After the patches which limit the attempts of doing remote name
resolving, there's an issue which prevents BlueZ to RNR new devices
for 5 minutes after reboot. It's caused by failed_time is init to 0,
and is then treated as the timestamp when the device failed RNR.
However, actually there is no failure yet.

This patch fixes it by always allowing RNR when failed_time = 0.
---

Changes in v2:
* Separate the one big if into multiple smaller ifs for clarity

 src/device.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/device.c b/src/device.c
index f2447c478e..6d29eb8966 100644
--- a/src/device.c
+++ b/src/device.c
@@ -4487,12 +4487,24 @@ bool device_is_name_resolve_allowed(struct btd_device *device)
 
 	clock_gettime(CLOCK_MONOTONIC, &now);
 
-	/* If now < failed_time, it means the clock has somehow turned back,
-	 * possibly because of system restart. Allow name request in this case.
+	/* failed_time is empty (0), meaning no prior failure. */
+	if (device->name_resolve_failed_time == 0)
+		return true;
+
+	/* now < failed_time, meaning the clock has somehow turned back,
+	 * possibly because of system restart. Allow just to be safe.
+	 */
+	if (now.tv_sec < device->name_resolve_failed_time)
+		return true;
+
+	/* now >= failed_time + name_request_retry_delay, meaning the
+	 * period of not sending name request is over.
 	 */
-	return now.tv_sec < device->name_resolve_failed_time ||
-		now.tv_sec >= device->name_resolve_failed_time +
-					btd_opts.name_request_retry_delay;
+	if (now.tv_sec >= device->name_resolve_failed_time +
+					btd_opts.name_request_retry_delay)
+		return true;
+
+	return false;
 }
 
 void device_name_resolve_fail(struct btd_device *device)
-- 
2.34.1.575.g55b058a8bb-goog