Hi Dmitry
On 8/21/2025 8:07 PM, Dmitry Baryshkov wrote:
> On Thu, Aug 21, 2025 at 07:50:01PM +0800, Shuai Zhang wrote:
>> When the host actively triggers SSR and collects coredump data,
>> the Bluetooth stack sends a reset command to the controller. However, due
>> to the inability to clear the QCA_SSR_TRIGGERED and QCA_IBS_DISABLED bits,
>> the reset command times out.
>>
>> To address this, this patch clears the QCA_SSR_TRIGGERED and
>> QCA_IBS_DISABLED flags and adds a 50ms delay after SSR, but only when
>> HCI_QUIRK_NON_PERSISTENT_SETUP is not set. This ensures the controller
>> completes the SSR process when BT_EN is always high due to hardware.
>>
>> For the purpose of HCI_QUIRK_NON_PERSISTENT_SETUP, please refer to
>> the comment in `include/net/bluetooth/hci.h`.
>>
>> The HCI_QUIRK_NON_PERSISTENT_SETUP quirk is associated with BT_EN,
>> and its presence can be used to determine whether BT_EN is defined in DTS.
>>
>> After SSR, host will not download the firmware, causing
>> controller to remain in the IBS_WAKE state. Host needs
>> to synchronize with the controller to maintain proper operation.
>>
>> Multiple triggers of SSR only first generate coredump file,
>> due to memcoredump_flag no clear.
>>
>> add clear coredump flag when ssr completed.
>>
>> When the SSR duration exceeds 2 seconds, it triggers
>> host tx_idle_timeout, which sets host TX state to sleep. due to the
>> hardware pulling up bt_en, the firmware is not downloaded after the SSR.
>> As a result, the controller does not enter sleep mode. Consequently,
>> when the host sends a command afterward, it sends 0xFD to the controller,
>> but the controller does not respond, leading to a command timeout.
>>
>> So reset tx_idle_timer after SSR to prevent host enter TX IBS_Sleep mode.
>>
>> Signed-off-by: Shuai Zhang <quic_shuaz@xxxxxxxxxxx>
>> ---
>> drivers/bluetooth/hci_qca.c | 33 +++++++++++++++++++++++++++++++++
>> 1 file changed, 33 insertions(+)
>>
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index 4e56782b0..9dc59b002 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -1653,6 +1653,39 @@ static void qca_hw_error(struct hci_dev *hdev, u8 code)
>> skb_queue_purge(&qca->rx_memdump_q);
>> }
>>
>> + /*
>> + * If the BT chip's bt_en pin is connected to a 3.3V power supply via
>> + * hardware and always stays high, driver cannot control the bt_en pin.
>> + * As a result, during SSR (SubSystem Restart), QCA_SSR_TRIGGERED and
>> + * QCA_IBS_DISABLED flags cannot be cleared, which leads to a reset
>> + * command timeout.
>> + * Add an msleep delay to ensure controller completes the SSR process.
>> + *
>> + * Host will not download the firmware after SSR, controller to remain
>> + * in the IBS_WAKE state, and the host needs to synchronize with it
>> + *
>> + * Since the bluetooth chip has been reset, clear the memdump state.
>> + */
>> + if (!test_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks)) {
>
> Why are you posting patches that don't even build? Which kernel version
> was used for developing this patch?
Sorry, due to my oversight, I used a newly created branch.
I will cherry-pick the patch to the linux-next master branch.
>
>> + /*
>> + * When the SSR (SubSystem Restart) duration exceeds 2 seconds,
>> + * it triggers host tx_idle_delay, which sets host TX state
>> + * to sleep. Reset tx_idle_timer after SSR to prevent
>> + * host enter TX IBS_Sleep mode.
>> + */
>> + mod_timer(&qca->tx_idle_timer, jiffies +
>> + msecs_to_jiffies(qca->tx_idle_delay));
>> +
>> + /* Controller reset completion time is 50ms */
>> + msleep(50);
>> +
>> + clear_bit(QCA_SSR_TRIGGERED, &qca->flags);
>> + clear_bit(QCA_IBS_DISABLED, &qca->flags);
>> +
>> + qca->tx_ibs_state = HCI_IBS_TX_AWAKE;
>> + qca->memdump_state = QCA_MEMDUMP_IDLE;
>> + }
>> +
>> clear_bit(QCA_HW_ERROR_EVENT, &qca->flags);
>> }
>>
>> --
>> 2.34.1
>>
>
BR,
Shuai
