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SubjectRe: [PATCH] mips/ad1843: convert time to jiffies HZ independent
At Sun, 14 Jun 2015 10:20:59 +0200,
Nicholas Mc Guire wrote:
>
> PI compliance scanning with coccinelle flagged:
> ./sound/mips/ad1843.c:503:2-32: WARNING:
> timeout (5) seems HZ dependent
>
> This was introduced in 'commit 862c2c0a61c5 ("ALSA: ALSA driver for SGI O2
> audio board")'. schedule_timeout_interruptible() expects a timeout in
> jiffies so the numeric constant makes the effective timeout HZ dependent.
> Simply put it through msecs_to_jiffies() to make it HZ independent.
>
> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> ---
>
> The loop here is bounded by 500 jiffies and it does not seem reasonable that
> it would loop 10 times faster on HZ=1000 configs over HZ=100 configs. The
> conversion via msecs_to_jiffies(5) ensures that it will loop at most 100
> times for all configs of HZ which seems reasonable (to me) but needs to be
> checked by someone that knows the details of this driver.

Using 5ms looks reasonable for this case. However,
schedule_timeout_interruptible() isn't. This is a loop that won't
break. So, the best would be to replace it with msleep() or its
friends.

> Note that the CONFIG_SND_PCM_OSS dependency was not listed in the
> Depends on: in Kconfig (which it probably should)

Why at all? It has nothing to do with OSS.


thanks,

Takashi


> Patch was compile tested with ip32_defconfig + CONFIG_SOUND=m,
> CONFIG_SND=m, CONFIG_SND_PCM_OSS=y, CONFIG_SND_SGI_O2=m
>
> Patch is against 4.1-rc7 (localversion-next is -next-20150612)
>
> sound/mips/ad1843.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/mips/ad1843.c b/sound/mips/ad1843.c
> index 5869075..ec22b55 100644
> --- a/sound/mips/ad1843.c
> +++ b/sound/mips/ad1843.c
> @@ -500,7 +500,7 @@ int ad1843_init(struct snd_ad1843 *ad1843)
> "ad1843: AD1843 won't power up\n");
> return -EIO;
> }
> - schedule_timeout_interruptible(5);
> + schedule_timeout_interruptible(msecs_to_jiffies(5));
> }
>
> /* 5. Power up the clock generators and enable clock output pins. */
> --
> 1.7.10.4
>


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