[PATCH] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

[PATCH] Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

[Vladimir V. Kondratyev]

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: e57362f4911b ("Bluetooth: btintel_pcie: Add support for _suspend() / _resume()")

Signed-off-by: Vladimir V. Kondratyev <vladimirkondratyev2@gmail.com>
---
 drivers/bluetooth/btintel_pcie.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index fda474406003..7fca8eea6e01 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -2778,9 +2778,13 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 					  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.
+		 * Refresh boot_stage_cache from hardware since it is only
+		 * updated by the interrupt handler, then check if the
+		 * controller reached the expected state and retry the
+		 * operation only if it hasn't.
 		 */
+		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;
-- 
2.54.0

RE: Bluetooth: btintel_pcie: fix stale cache in set_dxstate fallback check

[bluez.test.bot]

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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/project/bluetooth/list/?series=1091276

---Test result---

Test Summary:
CheckPatch                    PASS      0.69 seconds
GitLint                       PASS      0.30 seconds
SubjectPrefix                 PASS      0.11 seconds
BuildKernel                   PASS      27.57 seconds
CheckAllWarning               PASS      30.23 seconds
CheckSparse                   PASS      28.95 seconds
BuildKernel32                 PASS      27.07 seconds
TestRunnerSetup               PASS      582.94 seconds
IncrementalBuild              PASS      25.20 seconds



https://github.com/bluez/bluetooth-next/pull/155

---
Regards,
Linux Bluetooth