Hi Baochen,

On 2/20/24 7:17 PM, Baochen Qiang wrote:
Currently host relies on CE interrupts to get notified that
the service ready message is ready. This results in timeout
issue if the interrupt is not fired, due to some unknown
reasons. See below logs:

[76321.937866] ath10k_pci 0000:02:00.0: wmi service ready event not received
...
[76322.016738] ath10k_pci 0000:02:00.0: Could not init core: -110

And finally it causes WLAN interface bring up failure.

Change to give it one more chance here by polling CE rings,
before failing directly.

Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00157-QCARMSWPZ-1

Fixes: 5e3dd157d7e7 ("ath10k: mac80211 driver for Qualcomm Atheros 802.11ac CQA98xx 
devices")
Reported-by: James Prestwood <prest...@gmail.com>
Link: 
https://lore.kernel.org/linux-wireless/304ce305-fbe6-420e-ac2a-d61ae5e6c...@gmail.com/
Signed-off-by: Baochen Qiang <quic_bqi...@quicinc.com>
---
  drivers/net/wireless/ath/ath10k/wmi.c | 22 +++++++++++++++++++---
  1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/wmi.c 
b/drivers/net/wireless/ath/ath10k/wmi.c
index ddf15717d504..bf6cb2c73128 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -1763,12 +1763,28 @@ void ath10k_wmi_put_wmi_channel(struct ath10k *ar, 
struct wmi_channel *ch,
int ath10k_wmi_wait_for_service_ready(struct ath10k *ar)
  {
-       unsigned long time_left;
+       unsigned long time_left, i;
time_left = wait_for_completion_timeout(&ar->wmi.service_ready,
                                                WMI_SERVICE_READY_TIMEOUT_HZ);
-       if (!time_left)
-               return -ETIMEDOUT;
+       if (!time_left) {
+               /* Sometimes the PCI HIF doesn't receive interrupt
+                * for the service ready message even if the buffer
+                * was completed. PCIe sniffer shows that it's
+                * because the corresponding CE ring doesn't fires
+                * it. Workaround here by polling CE rings once.
+                */
+               ath10k_warn(ar, "failed to receive service ready completion, 
polling..\n");
+
+               for (i = 0; i < CE_COUNT; i++)
+                       ath10k_hif_send_complete_check(ar, i, 1);
+
+               time_left = wait_for_completion_timeout(&ar->wmi.service_ready,
+                                                       
WMI_SERVICE_READY_TIMEOUT_HZ);
+               if (!time_left)
+                       return -ETIMEDOUT;
+       }
+
        return 0;
  }
base-commit: 707e306f3573fa321ae197d77366578e4566cff5

Thank you for looking at this I will test this and see if it resolves the problem we're seeing but since its somewhat rare it may take me a bit to validate.

Is this any different than just trying to bring up the interface again from userspace? I could be wrong, but my concern with this is that when I retried in userspace things got into a very odd state:

 - IWD starts

 - ifdown interface

 - ifup interface, timeout -110

 - Retry ifup, success

 - Authenticate/associate succeed

 - 4-way handshake fails because the device never received the 1/4 frame.

IWD would then retry indefinitely with auth/assoc succeeding but never receiving any 4-way handshake frames. The only way to get things working again was reloading the ath10k driver/reboot. Maybe this patch is different because its waiting for the initial request and no issuing a second one? Just wanted to point that out in case it sheds any light.

Thanks,

James


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