Re: Kernel panic when SCO connection

[Ahmed Ragab <elmasri.ahmed@gmail.com>]

Hi Dev,

> 2. Increased transfer buffer size to 1.5K.

Please advise in which module should i increase the buffer size

Thanks

Ahmed



On 4 February 2010 13:36, SINGH DEVENDRA-DHGW76 <DevSingh@motorola.com> wrote:
> Hi,
>
> I noticed the same problem when I was working with a embedded board with
> Broadcom chipset and Linux kernel 2.6.18 (I guess). Use case was, a
> Bluetooth based headset sends data to the CSR Bluetooth dongle(USB),
> which in turn provide data to the Application through bluez stack.
>
>
> Following were my observation:
>
> 1. Board processor is not strong enough and so there was no URB in the
> queue and audio data was getting accumulated in the USB host controller.
> There are only 2 Rx URBs (hci_usb.h: #define HCI_MAX_ISOC_RX
> 2).
> 2. Actual length of data for data in the URB is reaching to the level of
> 1K bytes. (Max ISOC data length) however Bluetooth driver is expecting
> 10 packets of 64 bytes each. hci_usb_isoc_rx_submit function in
> hci_usb.c file.
> 3. Completion routine copies data for actual length returned for packet
> that could be 1024 while limit for one packet is 64B only. (hci_usb.c:
> hci_usb_rx_complete function).
> 4. These "SCO packet for unknown connection handle" error logs further
> complicated the problem as this will further eat-up cpu time.
>
>
> Cause:
>
> Max length of available transfer buffer could be 640 bytes (that's
> depend upon the buffer index) and copying big chunk of data was
> resulting into memory overrun and kernel memory was getting corrupted
> that results in un-expected behavior line connection break, lots of
> noise  and even kernel panic some times.
>
>
> Following was the work around:
>
> 1. Increased number of Rx URBs to 6. (hci_usb.h: #define HCI_MAX_ISOC_RX
> 6).
> 2. Increased transfer buffer size to 1.5K.
> 3. Put a check in completion routine that in case actual length is more
> then frame length then copy only frame length size data as follows:
>
> int len = (urb->iso_frame_desc[i].actual_length >
> urb->iso_frame_desc[i].length)?
>             urb->iso_frame_desc[i].length:
>             urb->iso_frame_desc[i].actual_length;
>
> __recv_frame(husb,
>                 _urb->type,
>                urb->transfer_buffer + urb->iso_frame_desc[i].offset,
>                len);
> 4. Logging "SCO packet for unknown connection handle" error only once
> for 100 errors. This will give more change to queue a URB as
> follows(hci_core.c:hci_scodata_packet function):
> hdev->stat.err_rx++;
> if(!(hdev->stat.err_rx % 100))
> {
>        BT_ERR("%s 100 SCO packets for unknown connection
> handles",hdev->name);
> }
>
>
> I must say that I did not try with latest Linux kernel however I could
> not see any code change regarding this functionality. Hope this will
> help.
>
> Regards,
> Dev
>
>
> -----Original Message-----
> From: linux-bluetooth-owner@vger.kernel.org
> [mailto:linux-bluetooth-owner@vger.kernel.org] On Behalf Of nirav rabara
> Sent: Wednesday, February 03, 2010 10:21 AM
> To: Gustavo F. Padovan
> Cc: linux-bluetooth@vger.kernel.org
> Subject: Re: Kernel panic when SCO connection
>
> - Show quoted text -
> On Tue, Feb 2, 2010 at 10:46 PM, Gustavo F. Padovan
> <padovan@profusion.mobi> wrote:
>> Hi Nirav,
>>
>> * nirav rabara <niravrabara@gmail.com> [2010-02-02 22:28:53 +0530]:
>>
>>> Hi,
>>> When I try to connect SCO socket, Kernel getting crash.
>>> Linux kernel - 2.6.22
>>> Bluez - 4.58
>>
>> Please try a 2.6.33 kernel and tell us if the bug still happens.
>>
>>>
>>> error message,
>>> __tx_submit:hci0 tx submit failed urb c0552c14 type 3 err -19
>>>
>>> sometimes in connection is showing error while connection as below,
>>> hci_acldata_packet:hci0 ACL packet data for unknown connection
>>> handler 2
>>>
>>> It would be really appreciable if  somebody put some on light on this
>
>>> issue, OR suggest me any patch or documentation.
>>>
>>> --
>>> With Regards,
>>> Nirav Rabara
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>>> linux-bluetooth" in the body of a message to
>>> majordomo@vger.kernel.org More majordomo info at
>>> http://vger.kernel.org/majordomo-info.html
>>
>> --
>> Gustavo F. Padovan
>> http://padovan.org
>>
>> ProFUSION embedded systems - http://profusion.mobi
>>
>
> Hi Gustavo,
>
> Thanks for your suggestion, but I am using bluez 4.58 on ATMEL
> AT91SAM9263, no patch available for the newer kernel 2.6.33 . Patches
> related to my board only available up to 2.6.30.
>
> It would be a great help if suggest me any alternet for this issue. OR
> any patches for the same problem as i mentioned for 2.6.22.
>
>
> --
> With Regards,
> Nirav Rabara
> --
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