[PATCH] net: ftgmac100: Enable TX interrupt to avoid TX timeout

[PATCH] net: ftgmac100: Enable TX interrupt to avoid TX timeout

[Jacky Chou]

Currently, the driver only enables RX interrupt to handle RX
packets and TX resources. Sometimes there is not RX traffic,
so the TX resource needs to wait for RX interrupt to free.
This situation will toggle the TX timeout watchdog when the MAC
TX ring has no more resources to transmit packets.
Therefore, enable TX interrupt to release TX resources at any time.

Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com>
---
 drivers/net/ethernet/faraday/ftgmac100.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/faraday/ftgmac100.h b/drivers/net/ethernet/faraday/ftgmac100.h
index 63b3e02fab16..4968f6f0bdbc 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.h
+++ b/drivers/net/ethernet/faraday/ftgmac100.h
@@ -84,7 +84,7 @@
 			    FTGMAC100_INT_RPKT_BUF)
 
 /* All the interrupts we care about */
-#define FTGMAC100_INT_ALL (FTGMAC100_INT_RPKT_BUF  |  \
+#define FTGMAC100_INT_ALL (FTGMAC100_INT_RXTX  |  \
 			   FTGMAC100_INT_BAD)
 
 /*
-- 
2.25.1

Re: [PATCH] net: ftgmac100: Enable TX interrupt to avoid TX timeout

[Andrew Lunn]

On Wed, Sep 04, 2024 at 06:31:16PM +0800, Jacky Chou wrote:
> Currently, the driver only enables RX interrupt to handle RX
> packets and TX resources. Sometimes there is not RX traffic,
> so the TX resource needs to wait for RX interrupt to free.
> This situation will toggle the TX timeout watchdog when the MAC
> TX ring has no more resources to transmit packets.
> Therefore, enable TX interrupt to release TX resources at any time.

This looks reasonable. FTGMAC100_INT_ALL is used when NAPI polling is
not being used, so the extra interrupts should not cause additional
load.

Is this a fix? How easy is it to trigger the issue?

   Andrew

Re: 回覆: [PATCH] net: ftgmac100: Enable TX interrupt to avoid TX timeout

[Andrew Lunn]

On Fri, Sep 06, 2024 at 01:57:56AM +0000, Jacky Chou wrote:
> Hello,
> 
> When I am verifying iperf3 over UDP, the network hangs.
> Like the log below.
> 
> root# iperf3 -c 192.168.100.100 -i1 -t10 -u -b0
> Connecting to host 192.168.100.100, port 5201
> [  4] local 192.168.100.101 port 35773 connected to 192.168.100.100 port 5201
> [ ID] Interval           Transfer     Bandwidth       Total Datagrams
> [  4]   0.00-20.42  sec   160 KBytes  64.2 Kbits/sec  20
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> [  4]  20.42-20.42  sec  0.00 Bytes  0.00 bits/sec  0
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth       Jitter    Lost/Total
> Datagrams
> [  4]   0.00-20.42  sec   160 KBytes  64.2 Kbits/sec  0.000 ms  0/20 (0%)
> [  4] Sent 20 datagrams
> iperf3: error - the server has terminated The network topology is FTGMAC
> connects directly to a PC. UDP does not need to wait for ACK, unlike TCP.
> Therefore, FTGMAC needs to enable TX interrupt to release TX resources instead
> of waiting for the RX interrupt.

Please don't top post.

So this does seem like a fix. Please read through:

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

You need a Fixes: tag, CC: stable tag, use the correct tree, etc.

    Andrew

---
pw-bot: cr

Re: [PATCH] net: ftgmac100: Enable TX interrupt to avoid TX timeout

[Jakub Kicinski]

On Wed, 4 Sep 2024 18:31:16 +0800 Jacky Chou wrote:
> Currently, the driver only enables RX interrupt to handle RX
> packets and TX resources. Sometimes there is not RX traffic,
> so the TX resource needs to wait for RX interrupt to free.
> This situation will toggle the TX timeout watchdog when the MAC
> TX ring has no more resources to transmit packets.
> Therefore, enable TX interrupt to release TX resources at any time.

Please answer Andrew's question (preferably send a v2 with the answer
as part of the commit message). Add a fixes tag, I think this is where
the bug was added?

Fixes: 10cbd6407609 ("ftgmac100: Rework NAPI & interrupts handling")

And when you send v2, please make sure to CC the author (Benjamin).
-- 
pw-bot: cr