Hi Oleksij,
Please try the attached patch. No valid ADC randomness will cause the issue.
--
Regards,
Miaoqing
> Hallo all,
>
> on my last train trip i noticed that ath9k-rng produce continuous 15%
> cpu load. Probably two factor coused this issue:
> - my STA was not associated with any AP
> - on the road there is enough noise.
>
> from why i see, this code has all reasons to consume all CPU time it
> get, so far ath9k_rng_data_read can provide some data.
>
> while (!kthread_should_stop()) {
> bytes_read = ath9k_rng_data_read(sc, rng_buf,
> ATH9K_RNG_BUF_SIZE);
> if (unlikely(!bytes_read)) {
> msleep_interruptible(10);
> continue;
> }
>
> /* sleep until entropy bits under write_wakeup_threshold
> */
> add_hwgenerator_randomness((void *)rng_buf, bytes_read,
> ATH9K_RNG_ENTROPY(bytes_read));
> }
>
> --
> Regards,
> Oleksij
>
>
>From b915bd98c523c39a6e8dd0a1c5046a6715a724d1 Mon Sep 17 00:00:00 2001
From: Miaoqing Pan <miaoq...@codeaurora.org>
Date: Fri, 11 Mar 2016 17:25:31 +0800
Subject: [PATCH] ath9k: fix rng high cpu load
Signed-off-by: Miaoqing Pan <miaoq...@codeaurora.org>
---
drivers/net/wireless/ath/ath9k/rng.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
index c9cb2aa..cf41f21 100644
--- a/drivers/net/wireless/ath/ath9k/rng.c
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -55,11 +55,24 @@ static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
return j << 2;
}
+static u32 ath9k_rng_delay_get(u32 fail_stats)
+{
+ if (fail_stats < 100)
+ delay = 10;
+ else if (fail_stats < 105)
+ delay = 1000;
+ else
+ delay = 10000;
+
+ return delay;
+}
+
static int ath9k_rng_kthread(void *data)
{
int bytes_read;
struct ath_softc *sc = data;
u32 *rng_buf;
+ u32 delay, fail_stats = 0;
rng_buf = kmalloc_array(ATH9K_RNG_BUF_SIZE, sizeof(u32), GFP_KERNEL);
if (!rng_buf)
@@ -69,10 +82,13 @@ static int ath9k_rng_kthread(void *data)
bytes_read = ath9k_rng_data_read(sc, rng_buf,
ATH9K_RNG_BUF_SIZE);
if (unlikely(!bytes_read)) {
- msleep_interruptible(10);
+ delay = ath9k_rng_delay_get(fail_stats++);
+ msleep_interruptible(delay);
continue;
}
+ fail_stats = 0;
+
/* sleep until entropy bits under write_wakeup_threshold */
add_hwgenerator_randomness((void *)rng_buf, bytes_read,
ATH9K_RNG_ENTROPY(bytes_read));
--
1.9.1
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