[PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[Ravindra]

MSIX_HW_INT_CAUSES is a write-one-to-clear register. Using a
read-modify-write helper writes zero to GP0, leaving the cause uncleared,
and can acknowledge unrelated pending causes through the read value.

Write only the GP0 bit directly, matching the interrupt handler's W1C
acknowledgment convention.

Fixes: 88c6216a52ea ("Bluetooth: btintel_pcie: Suspend/Resume: Controller doorbell interrupt handling")
Signed-off-by: Ravindra <ravindra@intel.com>
Tested-by: Sergey Lebedev <lsa.uz@pm.me>
Reviewed-by: Sergey Lebedev <lsa.uz@pm.me>
---
 drivers/bluetooth/btintel_pcie.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 553fa927cf0a..9fda057ca9a1 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -4217,10 +4217,12 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 				    "Timeout (%u ms) on alive interrupt for D%d entry, retry count %d",
 				    dx_intr_timeout_ms, dxstate, retry);
 
-			/* clear gp0 cause */
-			btintel_pcie_clr_reg_bits(data,
-						  BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
-						  BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
+			/* MSIX_HW_INT_CAUSES is W1C. Write only GP0 so other
+			 * pending causes are not acknowledged here.
+			 */
+			btintel_pcie_wr_reg32(data,
+					      BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
+					      BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
 		}
 
 		/* gp0_received is set at the top of the handler, before the switch on
-- 
2.43.0

RE: [v4,4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 863 bytes --]

This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----

error: patch failed: drivers/bluetooth/btintel_pcie.c:4217
error: drivers/bluetooth/btintel_pcie.c: patch does not apply
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"

Please resolve the issue and submit the patches again.


---
Regards,
Linux Bluetooth

Re: [PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Sun, 27 Sep 2026 20:53:56 +0530 you wrote:
> MSIX_HW_INT_CAUSES is a write-one-to-clear register. Using a
> read-modify-write helper writes zero to GP0, leaving the cause uncleared,
> and can acknowledge unrelated pending causes through the read value.
> 
> Write only the GP0 bit directly, matching the interrupt handler's W1C
> acknowledgment convention.
> 
> [...]

Here is the summary with links:
  - [v4,4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write
    https://git.kernel.org/bluetooth/bluetooth-next/c/6091d2771395

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

[PATCH v4 1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

[Ravindra]

From: "Vladimir V. Kondratyev" <vladimirkondratyev2@gmail.com>

btintel_pcie returns -16 (EBUSY) during suspend, causing the entire
suspend operation to abort on Intel Lunar Lake hardware. The system
immediately resumes after every suspend attempt:

  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 0
  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 1
  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 2
  btintel_pcie 0000:00:14.7: PM: pci_pm_suspend(): btintel_pcie_suspend [btintel_pcie] returns -16
  btintel_pcie 0000:00:14.7: PM: dpm_run_callback(): pci_pm_suspend returns -16
  btintel_pcie 0000:00:14.7: PM: failed to suspend async: error -16
  PM: Some devices failed to suspend, or early wake event detected

btintel_pcie_set_dxstate() falls back to checking the controller state via
btintel_pcie_in_d3/d0() when the alive interrupt is missed. However, these
helpers read boot_stage_cache, which is only updated by the interrupt
handler. As such, if the interrupt was missed, the cache is stale and the
fallback check always fails, exhausting all retries and returning -EBUSY,
causing suspend to abort.

The fix involves re-reading the hardware register before the fallback state
check, consistent with btintel_pcie_resume().

Fixes: 88c6216a52ea ("Bluetooth: btintel_pcie: Suspend/Resume: Controller doorbell interrupt handling")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221481
Link: https://lore.kernel.org/linux-bluetooth/20260830151550.44687-1-lsa.uz@pm.me/
Signed-off-by: Vladimir V. Kondratyev <vladimirkondratyev2@gmail.com>
Tested-by: Sergey Lebedev <lsa.uz@pm.me>
Signed-off-by: Sergey Lebedev <lsa.uz@pm.me>
---
 drivers/bluetooth/btintel_pcie.c | 8 +++++---
 drivers/bluetooth/btintel_pcie.h | 1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 59cf600014bb..677749903173 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -4222,10 +4222,12 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 					  BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
 					  BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
 
-		/* A hardware bug may cause the alive interrupt to be missed.
-		 * Check if the controller reached the expected state and retry
-		 * the operation only if it hasn't.
+		/* A hardware bug may cause the alive interrupt to be missed. Refresh
+		 * boot_stage_cache from hardware, since only the interrupt handler
+		 * updates it. Finally retry only if the state check still fails.
 		 */
+		data->boot_stage_cache = btintel_pcie_rd_reg32(data,
+							       BTINTEL_PCIE_CSR_BOOT_STAGE_REG);
 		if (dxstate == BTINTEL_PCIE_STATE_D0) {
 			if (btintel_pcie_in_d0(data))
 				return 0;
diff --git a/drivers/bluetooth/btintel_pcie.h b/drivers/bluetooth/btintel_pcie.h
index f35f80f800ed..016795fcbccc 100644
--- a/drivers/bluetooth/btintel_pcie.h
+++ b/drivers/bluetooth/btintel_pcie.h
@@ -51,6 +51,7 @@
 #define BTINTEL_PCIE_CSR_BOOT_STAGE_DEVICE_HALTED	(BIT(14))
 #define BTINTEL_PCIE_CSR_BOOT_STAGE_MAC_ACCESS_ON	(BIT(16))
 #define BTINTEL_PCIE_CSR_BOOT_STAGE_ALIVE		(BIT(23))
+/* Reflects live D-state. Updated by hardware on every D-state transition. */
 #define BTINTEL_PCIE_CSR_BOOT_STAGE_D3_STATE_READY	(BIT(24))
 
 #define BTINTEL_PCIE_CSR_DOORBELL_MBOX_READ_CONFIRM	(BIT(4))
-- 
2.43.0

[PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[Ravindra]

MSIX_HW_INT_CAUSES is a write-one-to-clear register. Using a
read-modify-write helper writes zero to GP0, leaving the cause uncleared,
and can acknowledge unrelated pending causes through the read value.

Write only the GP0 bit directly, matching the interrupt handler's W1C
acknowledgment convention.

Fixes: 88c6216a52ea ("Bluetooth: btintel_pcie: Suspend/Resume: Controller doorbell interrupt handling")
Signed-off-by: Ravindra <ravindra@intel.com>
---
 drivers/bluetooth/btintel_pcie.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 553fa927cf0a..9fda057ca9a1 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -4217,10 +4217,12 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 				    "Timeout (%u ms) on alive interrupt for D%d entry, retry count %d",
 				    dx_intr_timeout_ms, dxstate, retry);
 
-			/* clear gp0 cause */
-			btintel_pcie_clr_reg_bits(data,
-						  BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
-						  BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
+			/* MSIX_HW_INT_CAUSES is W1C. Write only GP0 so other
+			 * pending causes are not acknowledged here.
+			 */
+			btintel_pcie_wr_reg32(data,
+					      BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
+					      BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
 		}
 
 		/* gp0_received is set at the top of the handler, before the switch on
-- 
2.43.0

Re: [PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[Sergey Lebedev]

On a Surface Pro 11 (BE201 8086:a876) in s2idle, with the rest of v4,
including cycles that take the timeout path and so this write:

Tested-by: Sergey Lebedev <lsa.uz@pm.me>
Reviewed-by: Sergey Lebedev <lsa.uz@pm.me>