linux-kernel - [PATCH 2/2] bluetooth: raise HCI_CMD

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Date:	Wed, 14 May 2014 16:00:25 +0200
From:	Alexander Holler <holler@...oftware.de>
To:	linux-kernel@...r.kernel.org
Cc:	linux-bluetooth@...r.kernel.org,
	Marcel Holtmann <marcel@...tmann.org>,
	Gustavo Padovan <gustavo@...ovan.org>,
	Johan Hedberg <johan.hedberg@...il.com>,
	Alexander Holler <holler@...oftware.de>
Subject: [PATCH 2/2] bluetooth: raise HCI_CMD_TIMEOUT from 2s to 8s

The reasoning to do this is the following:

- If a timeout occurs, the HCI-communication is broken afterwards and the
  dongle isn't usable anymore.
- If it works after e.g. waiting 4s everyone is still happy but if it
  just breaks after only waiting 2s nothing is gained.
- Having to wait some more seconds until an error occurs doesn't change
  anything.

So there is no disadvantage in rasing the timeout but a great advantage
in case the dongle needs more than 2s to process an HCI command.
E.g. I had sometimes HCI command timeouts at boot (but never after the BT stack
was successfull started). I assume the reason might be the USB-probing which
happend before through the bootloader, which might have confused the dongle
such that it needs a bit more time, but I'm not sure.

Together with the patch which limits the timeout only to the actual time the
dongle needs to process an HCI command (and doesn't include the time the
kernel needs to process the answer to an HCI command), my problems were gone.

Signed-off-by: Alexander Holler <holler@...oftware.de>
---
 include/net/bluetooth/hci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index be150cf..d50fd34 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -180,7 +180,7 @@ enum {
 #define HCI_DISCONN_TIMEOUT	msecs_to_jiffies(2000)	/* 2 seconds */
 #define HCI_PAIRING_TIMEOUT	msecs_to_jiffies(60000)	/* 60 seconds */
 #define HCI_INIT_TIMEOUT	msecs_to_jiffies(10000)	/* 10 seconds */
-#define HCI_CMD_TIMEOUT		msecs_to_jiffies(2000)	/* 2 seconds */
+#define HCI_CMD_TIMEOUT		msecs_to_jiffies(8000)	/* 8 seconds */
 #define HCI_ACL_TX_TIMEOUT	msecs_to_jiffies(45000)	/* 45 seconds */
 #define HCI_AUTO_OFF_TIMEOUT	msecs_to_jiffies(2000)	/* 2 seconds */
 #define HCI_POWER_OFF_TIMEOUT	msecs_to_jiffies(5000)	/* 5 seconds */
-- 
1.8.3.1

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