iwlwifi: mvm: don't send the IWL_MVM_RXQ_NSSN_SYNC notif to Rx queues
diff mbox series

Message ID 20191120132628.30731-1-emmanuel.grumbach@intel.com
State Changes Requested
Delegated to: Kalle Valo
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Series
  • iwlwifi: mvm: don't send the IWL_MVM_RXQ_NSSN_SYNC notif to Rx queues
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Commit Message

Emmanuel Grumbach Nov. 20, 2019, 1:26 p.m. UTC
The purpose of this was to keep all the queues updated with
the Rx sequence numbers because unlikely yet possible
situations where queues can't understand if a specific
packet needs to be dropped or not.

Unfortunately, it was reported that this caused issues in
our DMA engine. We don't fully understand how this is related,
but this is being currently debugged. For now, just don't send
this notification to the Rx queues. This de-facto reverts my
commit 3c514bf831ac12356b695ff054bef641b9e99593:

iwlwifi: mvm: add a loose synchronization of the NSSN across Rx queues

This issue was reported here:
https://bugzilla.kernel.org/show_bug.cgi?id=204873
https://bugzilla.kernel.org/show_bug.cgi?id=205001
and others maybe.

Fixes: 3c514bf831ac ("iwlwifi: mvm: add a loose synchronization of the NSSN across Rx queues")
CC: <stable@vger.kernel.org> # 5.3+
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Kalle Valo Nov. 21, 2019, 6:32 p.m. UTC | #1
Emmanuel Grumbach <emmanuel.grumbach@intel.com> wrote:

> The purpose of this was to keep all the queues updated with
> the Rx sequence numbers because unlikely yet possible
> situations where queues can't understand if a specific
> packet needs to be dropped or not.
> 
> Unfortunately, it was reported that this caused issues in
> our DMA engine. We don't fully understand how this is related,
> but this is being currently debugged. For now, just don't send
> this notification to the Rx queues. This de-facto reverts my
> commit 3c514bf831ac12356b695ff054bef641b9e99593:
> 
> iwlwifi: mvm: add a loose synchronization of the NSSN across Rx queues
> 
> This issue was reported here:
> https://bugzilla.kernel.org/show_bug.cgi?id=204873
> https://bugzilla.kernel.org/show_bug.cgi?id=205001
> and others maybe.
> 
> Fixes: 3c514bf831ac ("iwlwifi: mvm: add a loose synchronization of the NSSN across Rx queues")
> CC: <stable@vger.kernel.org> # 5.3+
> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

New warning:

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c: In function 'iwl_mvm_sync_nssn':
drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c:517:32: warning: unused variable 'notif' [-Wunused-variable]
  struct iwl_mvm_rss_sync_notif notif = {
                                ^~~~~

Patch set to Changes Requested.

Patch
diff mbox series

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index 75a7af5ad7b2..8925fe5976cb 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -521,7 +521,11 @@  static void iwl_mvm_sync_nssn(struct iwl_mvm *mvm, u8 baid, u16 nssn)
 		.nssn_sync.nssn = nssn,
 	};
 
-	iwl_mvm_sync_rx_queues_internal(mvm, (void *)&notif, sizeof(notif));
+	/*
+	 * This allow to synchronize the queues, but it has been reported
+	 * to cause FH issues. Don't send the notification for now.
+	 * iwl_mvm_sync_rx_queues_internal(mvm, (void *)&notif, sizeof(notif));
+	 */
 }
 
 #define RX_REORDER_BUF_TIMEOUT_MQ (HZ / 10)