Re: [PATCH v5] Fix SSR(SubSystem Restart) fail when BT_EN is pulled up by hw

Dear,Paul

On 8/20/2025 9:32 PM, Paul Menzel wrote:

Dear Shuai,


Thank you for the improved version. The commit message summary/title still has the space missing before the ( and should be prefixed with `Bluetooth:` to pass the linters.

Am 20.08.25 um 14:06 schrieb Shuai Zhang:

quoted

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
commit 740011cfe948 ("Bluetooth: Add new quirk for non-persistent setup
settings")

Missing dot/period at the end.

Also, the comment in `include/net/bluetooth/hci.h` is more helpful to me than the commit.

quoted

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,
duo to memcoredump_flag no clear.

due to

quoted

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_Sloeep mode.

Sleep

quoted

Signed-off-by: Shuai Zhang <redacted>
---
  drivers/bluetooth/hci_qca.c | 31 +++++++++++++++++++++++++++++++
  1 file changed, 31 insertions(+)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 4e56782b0..403d65952 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c

@@ -1653,6 +1653,37 @@ 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

Missing space before (.

quoted

+     * 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)) {
+        /*
+         * When the SSR (Sub-System 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_Sloeep mode.

Sleep?

quoted

+         */
+        mod_timer(&qca->tx_idle_timer, jiffies +
+                  msecs_to_jiffies(qca->tx_idle_delay));
+        msleep(50);

Add a comment, why 50 ms and not 20 ms or 100 ms?

quoted

+
+        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);
  }
  

Kind regards,

Paul

Thanks again for your thorough check. 
I’ll revise the content and share the updated version soon


BR，
Shuai