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| author | Javier Nieto <jgnieto@cs.stanford.edu> | 2025-09-29 15:14:41 -0700 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2025-12-01 15:58:54 -0500 |
| commit | 01622e9a5336015f657df423b700e488fbcd2f39 (patch) | |
| tree | 80de90ae9dfc7585fcca90ec8cffb1346828514e /drivers | |
| parent | 484f1176896e85b5ae4f04403c8cd5b79aced95e (diff) | |
| download | linux-01622e9a5336015f657df423b700e488fbcd2f39.tar.gz | |
Bluetooth: hci_h5: avoid sending two SYNC messages
Previously, h5_open() called h5_link_control() to send a SYNC message.
But h5_link_control() only enqueues the packet and requires the caller
to call hci_uart_tx_wakeup(). Thus, after H5_SYNC_TIMEOUT ran out
(100ms), h5_timed_event() would be called and, realizing that the state
was still H5_UNINITIALIZED, it would re-enqueue the SYNC and call
hci_uart_tx_wakeup(). Consequently, two SYNC packets would be sent and
initialization would unnecessarily wait for 100ms.
The naive solution of calling hci_uart_tx_wakeup() in h5_open() does not
work because it will only schedule tx work if the HCI_PROTO_READY bit is
set and hci_serdev only sets it after h5_open() returns. This patch
removes the extraneous SYNC being enqueued and makes h5_timed_event()
wake up on the next jiffy.
Signed-off-by: Javier Nieto <jgnieto@cs.stanford.edu>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/bluetooth/hci_h5.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c index d0d4420c1a0f9a..863ee93dd8a8d9 100644 --- a/drivers/bluetooth/hci_h5.c +++ b/drivers/bluetooth/hci_h5.c @@ -213,7 +213,6 @@ static void h5_peer_reset(struct hci_uart *hu) static int h5_open(struct hci_uart *hu) { struct h5 *h5; - const unsigned char sync[] = { 0x01, 0x7e }; BT_DBG("hu %p", hu); @@ -243,9 +242,11 @@ static int h5_open(struct hci_uart *hu) set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags); - /* Send initial sync request */ - h5_link_control(hu, sync, sizeof(sync)); - mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT); + /* + * Wait one jiffy because the UART layer won't set HCI_UART_PROTO_READY, + * which allows us to send link packets, until this function returns. + */ + mod_timer(&h5->timer, jiffies + 1); return 0; } |