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SubjectRe: [PATCH 0/2] Quirk to enable QCA9377 to discover BLE devices
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Hi Joao Paulo,

> As reported previously on [1], it is currently not possible to discover
> BLE devices with QCA9377 controllers. When trying to start an active
> scanning procedure with this controller, three commands are queued,
> LE_SET_RANDOM_ADDR, LE_SET_SCAN_PARAM and LE_SET_SCAN_ENABLE. After the
> first command is sent to the controller, a command complete event for it
> is received, and the second command is sent, an extra command complete
> for the first command is received. At this point the kernel sends the
> next command and fails to process the command complete event for the
> LE_SET_SCAN_PARAM command, because when it arrives it does not match the
> last command that was sent. This makes hdev->le_scan_type never be
> updated and the kernel behaves as if a passive scanning procedure was
> being performed, thus no device found events are sent to userspace.
>
> [1] https://www.spinics.net/lists/linux-bluetooth/msg79102.html
>
> I have received no replies on the previous report and on further
> attempts to contact the QCA addresses that have submitted Bluetooth
> firmware blobs to linux-firmware upstream. This series avoids the
> problem described above, but I believe ideally the controller should not
> be sending this extra command complete event.
>
> I'm not 100% sure if the approach taken here is the best way to work
> around this problem in the kernel, as I am not super familiar with the
> HCI layer. I'll be happy to hear suggestions of better approaches.
>
> Full logs from btmon can be found bellow this message, and the extra
> command complete event can be seen at timestamp 27.420131.

so can we get a fixed firmware from Qualcomm? Or at least some ROM patches for it?

> Best regards,
>
> João Paulo Rechi Vita (2):
> Bluetooth: Create new HCI_QUIRK_WAIT_FOR_MATCHING_CC
> Bluetooth: Set HCI_QUIRK_WAIT_FOR_MATCHING_CC for QCA9377
>
> drivers/bluetooth/btusb.c | 9 +++++++++
> include/net/bluetooth/hci.h | 4 ++++
> include/net/bluetooth/hci_core.h | 1 +
> net/bluetooth/hci_core.c | 3 +++
> net/bluetooth/hci_event.c | 4 ++++
> 5 files changed, 21 insertions(+)
>
> --
> 2.20.1
>
> Bluetooth monitor ver 5.50
> = Note: Linux version 5.0.0+ (x86_64) 0.352340
> = Note: Bluetooth subsystem version 2.22 0.352343
> = New Index: 80:C5:F2:8F:87:84 (Primary,USB,hci0) [hci0] 0.352344
> = Open Index: 80:C5:F2:8F:87:84 [hci0] 0.352345
> = Index Info: 80:C5:F2:8F:87:84 (Qualcomm) [hci0] 0.352346
> @ MGMT Open: bluetoothd (privileged) version 1.14 {0x0001} 0.352347
> @ MGMT Open: btmon (privileged) version 1.14 {0x0002} 0.352366
> @ MGMT Open: btmgmt (privileged) version 1.14 {0x0003} 27.302164
> @ MGMT Command: Start Discovery (0x0023) plen 1 {0x0003} [hci0] 27.302310
> Address type: 0x06
> LE Public
> LE Random
> < HCI Command: LE Set Random Address (0x08|0x0005) plen 6 #1 [hci0] 27.302496
> Address: 15:60:F2:91:B2:24 (Non-Resolvable)
>> HCI Event: Command Complete (0x0e) plen 4 #2 [hci0] 27.419117
> LE Set Random Address (0x08|0x0005) ncmd 1
> Status: Success (0x00)
> < HCI Command: LE Set Scan Parameters (0x08|0x000b) plen 7 #3 [hci0] 27.419244
> Type: Active (0x01)
> Interval: 11.250 msec (0x0012)
> Window: 11.250 msec (0x0012)
> Own address type: Random (0x01)
> Filter policy: Accept all advertisement (0x00)
>> HCI Event: Command Complete (0x0e) plen 4 #4 [hci0] 27.420131
> LE Set Random Address (0x08|0x0005) ncmd 1
> Status: Success (0x00)

so we really need to ignore this command complete and not start ahead with the next command. Especially since we really only support one command at a time right now.

> < HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2 #5 [hci0] 27.420259
> Scanning: Enabled (0x01)
> Filter duplicates: Enabled (0x01)
>> HCI Event: Command Complete (0x0e) plen 4 #6 [hci0] 27.420969
> LE Set Scan Parameters (0x08|0x000b) ncmd 1
> Status: Success (0x00)

We need for this command complete to arrive and only then continue with LE Set Scan Enable. We don’t need a quirk for it. Just add support for dealing with unexpected command complete opcodes. And print a big error if that happens.

>> HCI Event: Command Complete (0x0e) plen 4 #7 [hci0] 27.421983
> LE Set Scan Enable (0x08|0x000c) ncmd 1
> Status: Success (0x00)
> @ MGMT Event: Command Complete (0x0001) plen 4 {0x0003} [hci0] 27.422059
> Start Discovery (0x0023) plen 1
> Status: Success (0x00)
> Address type: 0x06
> LE Public
> LE Random

Regards

Marcel

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