Hi Christian,
+ Max Chou as the author of commit 848fc6164158 ("Bluetooth: hci_h5:
btrtl: Add support for RTL8822C")
On Tue, Feb 21, 2023 at 8:13 AM Christian Hewitt
<christianshewitt@xxxxxxxxx> wrote:
[...]
> I can also use the oldest upstream firmware with the Armbian config:
>
> [ 7.315358] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000c lmp_ver=0a lmp_subver=8822
> [ 7.318754] Bluetooth: hci0: RTL: rom_version status=0 version=3
> [ 7.318772] Bluetooth: hci0: RTL: loading rtl_bt/rtl8822cs_fw.bin
> [ 7.319680] Bluetooth: hci0: RTL: loading rtl_bt/rtl8822cs_config.bin
> [ 7.341340] Bluetooth: hci0: RTL: cfg_sz 73, total sz 30817
> [ 7.612533] Bluetooth: hci0: RTL: fw version 0x05990d54
>
> The config file Armbian are using [0] is sourced from an Amlogic (Android) BSP
> repo shared to manufacturer Jethome (Vyacheslav on CC). There is no obvious
> version info. There are newer (more recently committed) config files available
> in updates to the Amlogic repo (alongside older 0599_0D54 firmware) and all work
> with any upstream firmware file.
I did compare the two config files and they differ in certain areas.
- upstream config: 1500000 baud, flow control is disabled
- Armbian config: 2000000 baud, flow control is enabled
Seeing that the Armbian config works with a higher baud rate my guess
is that there's some issue with flow control instead.
For those who are interested, here's the raw data provided by the
rtlfw tool from [0].
Armbian (= working) config:
Signature: 0x8723ab55
Data len: 67
len=16 offset=000c,{ 02 50 00 00 50 c5 ea 19 e1 1b fd af 5f 01 a4 0b
},UART_CONFIG
len=2 offset=01be,{ 1a 19 }
len=1 offset=01bb,{ 3d }
len=4 offset=01c0,{ 10 00 60 01 }
len=11 offset=1000,{ 00 ff 04 5d 00 03 00 ff ff ff ff }
len=11 offset=1040,{ 28 08 30 30 00 ff ff ff ff ff ff }
len=1 offset=01c4,{ 02 }
upstream (= non-working) config:
Signature: 0x8723ab55
Data len: 27
len=16 offset=000c,{ 02 80 92 04 50 c5 ea 19 e1 1b fd af 5b 01 a4 0b
},UART_CONFIG
len=1 offset=007a,{ 37 }
len=1 offset=00d9,{ 0f }
The baud rate is encoded in the first four bytes and can be decoded
with the help of btrtl_convert_baudrate() from Linux'
drivers/bluetooth/btrtl.c
Flow control is encoded as BIT(2) in data[12].
I am hoping that Hilda and/or Max can provide some ideas on how to
solve this issue.
Best regards,
Martin
[0] https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/tools/rtlfw.c?id=5d347b54714e0f2d750253be09b68b0c3119dd0a
