From: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx>
During firmware crash (or) user requested manual restart
the system gets into a soft lock up state because of the
below root cause.
During user requested hardware restart / firmware crash
the system goes into a soft lockup state as 'napi_synchronize'
is called after 'napi_disable' (which sets 'NAPI_STATE_SCHED'
bit) and it sleeps into infinite loop as it waits for
'NAPI_STATE_SCHED' to be cleared. This condition is hit because
'ath10k_hif_stop' is called twice as below (resulting in calling
'napi_synchronize' after 'napi_disable')
'ath10k_core_restart' -> 'ath10k_hif_stop' (ATH10K_STATE_ON) ->
-> 'ieee80211_restart_hw' -> 'ath10k_start' -> 'ath10k_halt' ->
'ath10k_core_stop' -> 'ath10k_hif_stop' (ATH10K_STATE_RESTARTING)
Fix this by calling 'ath10k_halt' in ath10k_core_restart itself
as it makes more sense before informing mac80211 to restart h/w
Also remove 'ath10k_halt' in ath10k_start for the state of 'restarting'
Fixes: 3c97f5de1f28 ("ath10k: implement NAPI support")
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx>
---
[v2 Added Fixes ]
drivers/net/wireless/ath/ath10k/core.c | 2 +-
drivers/net/wireless/ath/ath10k/mac.c | 1 -
2 files changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 7005e2a..5bc6847 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -1536,7 +1536,7 @@ static void ath10k_core_restart(struct work_struct *work)
switch (ar->state) {
case ATH10K_STATE_ON:
ar->state = ATH10K_STATE_RESTARTING;
- ath10k_hif_stop(ar);
+ ath10k_halt(ar);
ath10k_scan_finish(ar);
ieee80211_restart_hw(ar->hw);
break;
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 717b2fa..481842b 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -4449,7 +4449,6 @@ static int ath10k_start(struct ieee80211_hw *hw)
ar->state = ATH10K_STATE_ON;
break;
case ATH10K_STATE_RESTARTING:
- ath10k_halt(ar);
ar->state = ATH10K_STATE_RESTARTED;
break;
case ATH10K_STATE_ON:
--
1.9.1
