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* [PATCH v4 1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check
@ 2026-09-26  8:52 Ravindra
  2026-09-26  8:53 ` [PATCH v4 2/4] Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4 Ravindra
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Ravindra @ 2026-09-26  8:52 UTC (permalink / raw)
  To: linux-bluetooth, lsa.uz, vladimirkondratyev2
  Cc: chethan.tumkur.narayan, kiran.k, Paul Menzel

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


^ permalink raw reply related	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2026-09-29 15:10 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-09-26  8:52 [PATCH v4 1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check Ravindra
2026-09-26  8:53 ` [PATCH v4 2/4] Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4 Ravindra
2026-09-26  8:53 ` [PATCH v4 3/4] Bluetooth: btintel_pcie: verify state after alive interrupt Ravindra
2026-09-26  8:53 ` [PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write Ravindra
2026-09-26 14:45   ` Sergey Lebedev
2026-09-27 23:23 ` [v4,1/4] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check bluez.test.bot
2026-09-29 15:10 ` [PATCH v4 1/4] " patchwork-bot+bluetooth

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