[PATCH v5 0/4] Bluetooth: btintel_pcie: fix D-state transition and PM flows

[PATCH v5 0/4] Bluetooth: btintel_pcie: fix D-state transition and PM flows

[Ravindra]

This series fixes the suspend/resume path of btintel_pcie.

Patch 1 re-reads the boot stage register before the fallback state check,
so a missed alive interrupt no longer leaves btintel_pcie_set_dxstate()
testing a stale cache and aborting suspend with -EBUSY.

Patch 2 distinguishes S0ix from S3/S4 so the controller is placed in the
correct D-state, and routes .thaw through a normal D0 transition instead
of an unnecessary FLR.

Patch 3 stops treating gp0_received as proof that the requested D-state
transition completed. The flag is set at the top of the GP0 handler,
before the switch on alive_intr_ctxt, so a matched case can return having
changed nothing. The state is now verified against the register, and the
handler's work is completed from the fallback when needed.

Patch 4 clears the GP0 cause with a direct W1C write. The previous
read-modify-write helper wrote zero to GP0, leaving it uncleared, and
could acknowledge unrelated pending causes.

Changes in v5:
- Resend of the full series. v4 4/4 was posted on its own and could not be
  applied by CI, because its context depends on 3/4.
- 4/4: picked up Sergey's Tested-by and Reviewed-by.
- No functional changes since v4.

Changes in v4:
- 3/4: verify the state after the alive interrupt instead of trusting
  gp0_received, keep the flag reset inside the retry loop, complete the
  mbox<->alive handshake, propagate btintel_pcie_start_rx() errors, and
  restore the D3 context when the handler did not record it.
- 4/4: replace the W1C read-modify-write with a direct GP0 write.
- 1/4: corrected the Fixes: tag.

Ravindra (2):
  Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4
  Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

Sergey Lebedev (1):
  Bluetooth: btintel_pcie: verify state after alive interrupt

Vladimir V. Kondratyev (1):
  Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

 drivers/bluetooth/btintel_pcie.c | 124 ++++++++++++++++++++++---------
 drivers/bluetooth/btintel_pcie.h |   3 +-
 2 files changed, 91 insertions(+), 36 deletions(-)

-- 
2.43.0

[PATCH v5 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

RE: Bluetooth: btintel_pcie: fix D-state transition and PM flows

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2524 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/series/1174933/

---Test result---

Test Summary:
CheckPatch                    FAIL      2.96 seconds
VerifyFixes                   PASS      0.09 seconds
VerifySignedoff               PASS      0.09 seconds
GitLint                       FAIL      1.06 seconds
SubjectPrefix                 PASS      0.35 seconds
BuildKernel                   PASS      29.05 seconds
CheckAllWarning               PASS      32.86 seconds
CheckSparse                   PASS      35.64 seconds
BuildKernel32                 PASS      28.71 seconds
CheckKernelLLVM               PASS      40.18 seconds
TestRunnerSetup               PASS      791.92 seconds
IncrementalBuild              PASS      31.38 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
[v5,1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check
WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
#90: 
  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 0

total: 0 errors, 1 warnings, 22 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

/home/runner/work/bluetooth-next/bluetooth-next/src/patch/14851174.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
[v5,1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

9: B1 Line exceeds max length (82>80): "  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 0"
10: B1 Line exceeds max length (82>80): "  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 1"
11: B1 Line exceeds max length (82>80): "  Bluetooth: hci0: Timeout (200 ms) on alive interrupt for D2 entry, retry count 2"
12: B1 Line exceeds max length (98>80): "  btintel_pcie 0000:00:14.7: PM: pci_pm_suspend(): btintel_pcie_suspend [btintel_pcie] returns -16"


https://github.com/bluez/bluetooth-next/pull/831

---
Regards,
Linux Bluetooth

[PATCH v5 2/4] Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4

[Ravindra]

Fix two issues in the PM suspend/resume path:

1. S3 was handled the same as S0ix, keeping the controller on the
   D3hot-style path. That caused resume instability because S3 can
   remove power from the controller, unlike s2idle/S0ix. Use
   pm_suspend_target_state to distinguish them: D3_HOT for S0ix and
   D3_COLD for S3/S4. Add .restore to force FLR-based firmware recovery
   after S4 and S3 (PM_SUSPEND_MEM), as power is lost. S0ix resumes via
   a normal D0 transition.

2. During hibernation, .freeze() puts the controller into the D3cold
   state without any loss of power, and the flow normally continues to
   .poweroff(). If hibernation instead fails, .thaw() is called to bring
   the controller back up, and the old code routed it through
   btintel_pcie_resume(), which forced FLR-based firmware recovery
   whenever data->pm_sx_event was PM_EVENT_FREEZE. That check was
   incorrect: since the controller's power was never actually removed on
   this failed-hibernation path, FLR-based recovery is unnecessary. Remove
   pm_sx_event and route .thaw through a normal D0 transition instead;
   FLR-based recovery is retained only in .restore, where genuine S4
   power loss requires it.

Tested with:
  S0ix: sudo sh -c 'echo "+40" > /sys/class/rtc/rtc0/wakealarm' && \
        echo freeze | sudo tee /sys/power/state
  S3:   sudo rtcwake -m mem  -s 60
  S4:   sudo rtcwake -m disk -s 60

Fixes: e57362f4911b ("Bluetooth: btintel_pcie: Add support for _suspend() / _resume()")
Assisted-by: GitHub-Copilot:GPT5
Signed-off-by: Ravindra <ravindra@intel.com>
Tested-by: Sergey Lebedev <lsa.uz@pm.me>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
---
 drivers/bluetooth/btintel_pcie.c | 58 +++++++++++++++++++++-----------
 drivers/bluetooth/btintel_pcie.h |  2 --
 2 files changed, 39 insertions(+), 21 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 677749903173..082f5ec8ba71 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -16,6 +16,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/acpi.h>
+#include <linux/suspend.h>
 
 #include <linux/unaligned.h>
 #include <linux/devcoredump.h>
@@ -4199,7 +4200,8 @@ static void btintel_pcie_coredump(struct device *dev)
 
 static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 {
-	int retry = 0, status;
+	int retry = 0;
+	long status;
 	u32 dx_intr_timeout_ms = 200;
 
 	do {
@@ -4251,18 +4253,23 @@ static int btintel_pcie_suspend_late(struct device *dev, pm_message_t mesg)
 
 	data = pci_get_drvdata(pdev);
 
-	dxstate = (mesg.event == PM_EVENT_SUSPEND ?
-		   BTINTEL_PCIE_STATE_D3_HOT : BTINTEL_PCIE_STATE_D3_COLD);
-
-	data->pm_sx_event = mesg.event;
+	/* S0ix (s2idle) uses D3_HOT; S3, freeze and hibernate use D3_COLD. */
+	if (mesg.event == PM_EVENT_SUSPEND &&
+	    pm_suspend_target_state == PM_SUSPEND_TO_IDLE)
+		dxstate = BTINTEL_PCIE_STATE_D3_HOT;
+	else
+		dxstate = BTINTEL_PCIE_STATE_D3_COLD;
 
 	start = ktime_get();
 
 	/* Refer: 6.4.11.7 -> Platform power management */
 	err = btintel_pcie_set_dxstate(data, dxstate);
 
-	if (err)
+	if (err) {
+		bt_dev_err(data->hdev, "Failed to set dxstate:%u (%d)",
+			   dxstate, err);
 		return err;
+	}
 
 	bt_dev_dbg(data->hdev,
 		   "device entered into d3 state from d0 in %lld us",
@@ -4285,7 +4292,7 @@ static int btintel_pcie_freeze(struct device *dev)
 	return btintel_pcie_suspend_late(dev, PMSG_FREEZE);
 }
 
-static int btintel_pcie_resume(struct device *dev)
+static int btintel_pcie_resume_event(struct device *dev, pm_message_t mesg)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct btintel_pcie_data *data;
@@ -4293,19 +4300,15 @@ static int btintel_pcie_resume(struct device *dev)
 	int err;
 
 	data = pci_get_drvdata(pdev);
-	data->gp0_received = false;
 
 	start = ktime_get();
 
-	/* When the system enters S4 (hibernate) mode, bluetooth device loses
-	 * power, which results in the erasure of its loaded firmware.
-	 * Consequently, function level reset (flr) is required on system
-	 * resume to bring the controller back into an operational state by
-	 * initiating a new firmware download.
+	/* S3 and S4 may cut power, erasing the firmware. Force FLR to recover
+	 * instead of a normal D0 transition.
 	 */
-
-	if (data->pm_sx_event == PM_EVENT_FREEZE ||
-	    data->pm_sx_event == PM_EVENT_HIBERNATE) {
+	if (mesg.event == PM_EVENT_RESTORE ||
+	    (mesg.event == PM_EVENT_RESUME &&
+	     pm_suspend_target_state == PM_SUSPEND_MEM)) {
 		set_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags);
 		btintel_pcie_request_reset(data, BTINTEL_PCIE_IOSF_PRR_FLR);
 		return 0;
@@ -4314,7 +4317,9 @@ static int btintel_pcie_resume(struct device *dev)
 	/* Refer: 6.4.11.7 -> Platform power management */
 	err = btintel_pcie_set_dxstate(data, BTINTEL_PCIE_STATE_D0);
 
-	if (err == 0) {
+	if (err) {
+		bt_dev_err(data->hdev, "Failed to set D0 state (%d)", err);
+	} else {
 		bt_dev_dbg(data->hdev,
 			   "device entered into d0 state from d3 in %lld us",
 			   ktime_to_us(ktime_get() - start));
@@ -4339,13 +4344,28 @@ static int btintel_pcie_resume(struct device *dev)
 	return err;
 }
 
+static int btintel_pcie_resume(struct device *dev)
+{
+	return btintel_pcie_resume_event(dev, PMSG_RESUME);
+}
+
+static int btintel_pcie_restore(struct device *dev)
+{
+	return btintel_pcie_resume_event(dev, PMSG_RESTORE);
+}
+
+static int btintel_pcie_thaw(struct device *dev)
+{
+	return btintel_pcie_resume_event(dev, PMSG_THAW);
+}
+
 static const struct dev_pm_ops btintel_pcie_pm_ops = {
 	.suspend = btintel_pcie_suspend,
 	.resume = btintel_pcie_resume,
 	.freeze = btintel_pcie_freeze,
-	.thaw = btintel_pcie_resume,
+	.thaw = btintel_pcie_thaw,
 	.poweroff = btintel_pcie_hibernate,
-	.restore = btintel_pcie_resume,
+	.restore = btintel_pcie_restore,
 };
 
 static struct pci_driver btintel_pcie_driver = {
diff --git a/drivers/bluetooth/btintel_pcie.h b/drivers/bluetooth/btintel_pcie.h
index 016795fcbccc..3030b4e8b750 100644
--- a/drivers/bluetooth/btintel_pcie.h
+++ b/drivers/bluetooth/btintel_pcie.h
@@ -713,7 +713,6 @@ struct btintel_pcie_ini_dump_info {
  * @txq: TX Queue struct
  * @rxq: RX Queue struct
  * @alive_intr_ctxt: Alive interrupt context
- * @pm_sx_event: PM event on which system got suspended
  */
 struct btintel_pcie_data {
 	struct pci_dev	*pdev;
@@ -773,7 +772,6 @@ struct btintel_pcie_data {
 	struct btintel_pcie_dbgc	dbgc;
 	struct btintel_pcie_mdbgc	mdbgc;
 	struct btintel_pcie_dump_header dmp_hdr;
-	u8	pm_sx_event;
 	u32	debug_evt_addr;
 	u32	debug_evt_size;
 	dma_addr_t	debug_table_addr;
-- 
2.43.0

[PATCH v5 3/4] Bluetooth: btintel_pcie: verify state after alive interrupt

[Ravindra]

From: Sergey Lebedev <lsa.uz@pm.me>

The gp0_received flag only reports that the GP0 handler ran. It does
not guarantee that the handler completed the requested D-state
transition: a matched case can leave the state unchanged.

Refresh the boot-stage register before treating the transition as
successful. When the controller is in D0 but the handler did not
re-arm the interface, restore the alive context, reset the interface
arrays, restart RX, and complete the mailbox/alive handshake. Propagate
RX setup failures to the PM caller. Likewise, when the controller is in
D3 but the handler did not record it, restore the alive context so the
next transition dispatches correctly.

Signed-off-by: Ravindra <ravindra@intel.com>
Signed-off-by: Sergey Lebedev <lsa.uz@pm.me>
---
 drivers/bluetooth/btintel_pcie.c | 64 ++++++++++++++++++++++++--------
 1 file changed, 48 insertions(+), 16 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 082f5ec8ba71..553fa927cf0a 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -4200,7 +4200,7 @@ static void btintel_pcie_coredump(struct device *dev)
 
 static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 {
-	int retry = 0;
+	int retry = 0, err;
 	long status;
 	u32 dx_intr_timeout_ms = 200;
 
@@ -4212,30 +4212,62 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 		status = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
 			msecs_to_jiffies(dx_intr_timeout_ms));
 
-		if (status)
-			return 0;
-
-		bt_dev_warn(data->hdev,
-			   "Timeout (%u ms) on alive interrupt for D%d entry, retry count %d",
-			   dx_intr_timeout_ms, dxstate, retry);
+		if (!status) {
+			bt_dev_warn(data->hdev,
+				    "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);
+			/* clear gp0 cause */
+			btintel_pcie_clr_reg_bits(data,
+						  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. Refresh
-		 * boot_stage_cache from hardware, since only the interrupt handler
-		 * updates it. Finally retry only if the state check still fails.
+		/* gp0_received is set at the top of the handler, before the switch on
+		 * alive_intr_ctxt. Error and lockdown are filtered out above it, but a
+		 * matched case can still complete without doing anything - D3 breaks
+		 * unchanged while the controller has not reached D0 - and a hardware
+		 * bug may drop the interrupt outright. Either way the flag says a gp0
+		 * was handled, not that the transition completed, and only the register
+		 * knows. Refresh the cache here and 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))
+			if (btintel_pcie_in_d0(data)) {
+				/* Do what the handler's D3 -> D0 branch
+				 * would have done, unless it already has.
+				 */
+				if (data->alive_intr_ctxt == BTINTEL_PCIE_D0)
+					return 0;
+
+				data->alive_intr_ctxt = BTINTEL_PCIE_D0;
+				btintel_pcie_reset_ia(data);
+				err = btintel_pcie_start_rx(data);
+				if (err)
+					return err;
+
+				/* Complete the mbox<->alive handshake */
+				if (test_and_clear_bit(BTINTEL_PCIE_MBOX_PARSE_PENDING,
+						       &data->flags)) {
+					set_bit(BTINTEL_PCIE_MBOX_PARSE_READY, &data->flags);
+					wake_up(&data->mbox_parse_wait_q);
+				}
+
 				return 0;
+			}
 		} else {
-			if (btintel_pcie_in_d3(data))
+			if (btintel_pcie_in_d3(data)) {
+				/* Do what the handler's D0 -> D3 branch
+				 * would have done, unless it already has.
+				 */
+				if (data->alive_intr_ctxt == BTINTEL_PCIE_D3)
+					return 0;
+
+				data->alive_intr_ctxt = BTINTEL_PCIE_D3;
 				return 0;
+			}
 		}
 
 	} while (++retry < BTINTEL_PCIE_DX_TRANSITION_MAX_RETRIES);
-- 
2.43.0

RE: [PATCH v5 3/4] Bluetooth: btintel_pcie: verify state after alive interrupt

[Ravindra]

Hi Sergey,

On Patch 3:
I checked the Sashiko review comments for patch 3:
https://sashiko.dev/#/patchset/20260928050344.2893790-1-ravindra%40intel.com

Your concern is valid. The GP0 threaded IRQ handler and set_dxstate()
fallback can race if the interrupt is delayed or the PM wait times out.
Both paths could claim D0, reset the IA arrays, and re-arm RX concurrently.

I updated patch 3 to serialize the alive_intr_ctxt claim using irq_lock.
Only the winner performs btintel_pcie_reset_ia() and
btintel_pcie_start_rx(); the other path observes the completed state.

The D3 fallback update is protected by the same synchronization. The
changes are folded into patch 3, with no separate patch.

Subject:
Bluetooth: btintel_pcie: verify and serialize D-state transitions

I also added the Co-developed-by me, Fixes, and Tested-by as you tags while
retaining you as the patch author as you. Checkpatch and the driver build pass.
I will be sending this as v6 which includes all the 4 patches and
all the required changes.

On Path 2: Does this logic correctly handle wakeups from hybrid sleep?

if (mesg.event == PM_EVENT_RESUME &&
    pm_suspend_target_state == PM_SUSPEND_MEM)

This condition handles wakeup from hybrid sleep.

PM_EVENT_THAW is called when hibernation is aborted.
Already addressed in previous patch comments.

Best regards,
Ravindra

> Subject: [PATCH v5 3/4] Bluetooth: btintel_pcie: verify state after alive
> interrupt
> 
> From: Sergey Lebedev <lsa.uz@pm.me>
> 
> The gp0_received flag only reports that the GP0 handler ran. It does not
> guarantee that the handler completed the requested D-state
> transition: a matched case can leave the state unchanged.
> 
> Refresh the boot-stage register before treating the transition as successful.
> When the controller is in D0 but the handler did not re-arm the interface,
> restore the alive context, reset the interface arrays, restart RX, and complete
> the mailbox/alive handshake. Propagate RX setup failures to the PM caller.
> Likewise, when the controller is in
> D3 but the handler did not record it, restore the alive context so the next
> transition dispatches correctly.
> 
> Signed-off-by: Ravindra <ravindra@intel.com>
> Signed-off-by: Sergey Lebedev <lsa.uz@pm.me>
> ---
>  drivers/bluetooth/btintel_pcie.c | 64 ++++++++++++++++++++++++--------
>  1 file changed, 48 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
> index 082f5ec8ba71..553fa927cf0a 100644
> --- a/drivers/bluetooth/btintel_pcie.c
> +++ b/drivers/bluetooth/btintel_pcie.c
> @@ -4200,7 +4200,7 @@ static void btintel_pcie_coredump(struct device
> *dev)
> 
>  static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
> {
> -	int retry = 0;
> +	int retry = 0, err;
>  	long status;
>  	u32 dx_intr_timeout_ms = 200;
> 
> @@ -4212,30 +4212,62 @@ static int btintel_pcie_set_dxstate(struct
> btintel_pcie_data *data, u32 dxstate)
>  		status = wait_event_timeout(data->gp0_wait_q, data-
> >gp0_received,
>  			msecs_to_jiffies(dx_intr_timeout_ms));
> 
> -		if (status)
> -			return 0;
> -
> -		bt_dev_warn(data->hdev,
> -			   "Timeout (%u ms) on alive interrupt for D%d entry,
> retry count %d",
> -			   dx_intr_timeout_ms, dxstate, retry);
> +		if (!status) {
> +			bt_dev_warn(data->hdev,
> +				    "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);
> +			/* clear gp0 cause */
> +			btintel_pcie_clr_reg_bits(data,
> +
> 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.
> Refresh
> -		 * boot_stage_cache from hardware, since only the interrupt
> handler
> -		 * updates it. Finally retry only if the state check still fails.
> +		/* gp0_received is set at the top of the handler, before the
> switch on
> +		 * alive_intr_ctxt. Error and lockdown are filtered out above it,
> but a
> +		 * matched case can still complete without doing anything -
> D3 breaks
> +		 * unchanged while the controller has not reached D0 - and a
> hardware
> +		 * bug may drop the interrupt outright. Either way the flag
> says a gp0
> +		 * was handled, not that the transition completed, and only
> the register
> +		 * knows. Refresh the cache here and 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))
> +			if (btintel_pcie_in_d0(data)) {
> +				/* Do what the handler's D3 -> D0 branch
> +				 * would have done, unless it already has.
> +				 */
> +				if (data->alive_intr_ctxt == BTINTEL_PCIE_D0)
> +					return 0;
> +
> +				data->alive_intr_ctxt = BTINTEL_PCIE_D0;
> +				btintel_pcie_reset_ia(data);
> +				err = btintel_pcie_start_rx(data);
> +				if (err)
> +					return err;
> +
> +				/* Complete the mbox<->alive handshake */
> +				if
> (test_and_clear_bit(BTINTEL_PCIE_MBOX_PARSE_PENDING,
> +						       &data->flags)) {
> +
> 	set_bit(BTINTEL_PCIE_MBOX_PARSE_READY, &data->flags);
> +					wake_up(&data-
> >mbox_parse_wait_q);
> +				}
> +
>  				return 0;
> +			}
>  		} else {
> -			if (btintel_pcie_in_d3(data))
> +			if (btintel_pcie_in_d3(data)) {
> +				/* Do what the handler's D0 -> D3 branch
> +				 * would have done, unless it already has.
> +				 */
> +				if (data->alive_intr_ctxt == BTINTEL_PCIE_D3)
> +					return 0;
> +
> +				data->alive_intr_ctxt = BTINTEL_PCIE_D3;
>  				return 0;
> +			}
>  		}
> 
>  	} while (++retry < BTINTEL_PCIE_DX_TRANSITION_MAX_RETRIES);
> --
> 2.43.0

[PATCH v5 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: [PATCH v5 0/4] Bluetooth: btintel_pcie: fix D-state transition and PM flows

[patchwork-bot+bluetooth]

Hello:

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

On Mon, 28 Sep 2026 10:33:40 +0530 you wrote:
> This series fixes the suspend/resume path of btintel_pcie.
> 
> Patch 1 re-reads the boot stage register before the fallback state check,
> so a missed alive interrupt no longer leaves btintel_pcie_set_dxstate()
> testing a stale cache and aborting suspend with -EBUSY.
> 
> Patch 2 distinguishes S0ix from S3/S4 so the controller is placed in the
> correct D-state, and routes .thaw through a normal D0 transition instead
> of an unnecessary FLR.
> 
> [...]

Here is the summary with links:
  - [v5,1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check
    https://git.kernel.org/bluetooth/bluetooth-next/c/20dfccf8d854
  - [v5,2/4] Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4
    https://git.kernel.org/bluetooth/bluetooth-next/c/79463c0de429
  - [v5,3/4] Bluetooth: btintel_pcie: verify state after alive interrupt
    (no matching commit)
  - [v5,4/4] 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!
-- 
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