New: Some ACPI discovered BRCM HCI UART chip write clock failed.
https://bugzilla.kernel.org/show_bug.cgi?id=207843
Bug ID: 207843
Summary: Some ACPI discovered BRCM HCI UART chip write clock
failed.
Product: Drivers
Version: 2.5
Kernel Version: 5.6.13
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: low
Priority: P1
Component: Bluetooth
Assignee: [email protected]
Reporter: [email protected]
Regression: NoCreated attachment 289213
--> https://bugzilla.kernel.org/attachment.cgi?id=289213&action=edit
dmesg output
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Overview:
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My tablet uses AP6255 wifi/bluetooth module with BCM43455 chip. The bluetooth controller worked well except bluetooth headset play sound glitch.It's not configuration problem in bluez or pulseaudio. Some log in dmesg indicated that baud rate was not correctly configured. dmesg:
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Bluetooth: BCM: failed to write clock (-56)
Bluetooth: Failed to set baudrate.Steps to Reproduce:
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1. Power on bluetooth headset.
2. If it was not automatically connect, connect to headset by bluetoothctl.
3. play sound.Actual Results:
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sound glitches.
Expect Results:
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sound well.
Additional Information:
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I suspect the baud rate was too low to transmit audio.
It seems the chip can't support write clock HCI command. Then bluetooth driver used default 115200 baud rate.
I tried to force configure 4Mbps baud rate to my chip after write clock failed, but reset it failed. Then I hardcode baud rate to 3Mbps, it solved the glitch problem.
And I found the commit that introduced the 4Mbsp to ACPI device:
https://github.com/torvalds/linux/commit/74183a1c50a3c61e62d2e585107ea3c0b942a3ff
It seems not all ACPI discovered devices can support write clock. So maybe the driver should fallback baud rate to 3Mbps if write clock failed.
Signature · 5 lines
Smiles ^__________^ zech -- You are receiving this mail because: You are the assignee for the bug.