]> www.infradead.org Git - users/jedix/linux-maple.git/commit
Bluetooth: btqcomsmd: Fix command timeout after setting BD address
authorStephan Gerhold <stephan.gerhold@kernkonzept.com>
Wed, 8 Mar 2023 13:31:55 +0000 (14:31 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 30 Mar 2023 10:49:12 +0000 (12:49 +0200)
commit95085960062ddd3139810dfe95b901834ffee221
tree2b101b9a0ab8d7a61265e2e3370ace227b329061
parent612cf2495ec6cf5834e8b4a70f599190c35cf8c8
Bluetooth: btqcomsmd: Fix command timeout after setting BD address

[ Upstream commit 5d44ab9e204200a78ad55cdf185aa2bb109b5950 ]

On most devices using the btqcomsmd driver (e.g. the DragonBoard 410c
and other devices based on the Qualcomm MSM8916/MSM8909/... SoCs)
the Bluetooth firmware seems to become unresponsive for a while after
setting the BD address. On recent kernel versions (at least 5.17+)
this often causes timeouts for subsequent commands, e.g. the HCI reset
sent by the Bluetooth core during initialization:

    Bluetooth: hci0: Opcode 0x c03 failed: -110

Unfortunately this behavior does not seem to be documented anywhere.
Experimentation suggests that the minimum necessary delay to avoid
the problem is ~150us. However, to be sure add a sleep for > 1ms
in case it is a bit longer on other firmware versions.

Older kernel versions are likely also affected, although perhaps with
slightly different errors or less probability. Side effects can easily
hide the issue in most cases, e.g. unrelated incoming interrupts that
cause the necessary delay.

Fixes: 1511cc750c3d ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/bluetooth/btqcomsmd.c