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Re: [PATCH] drivers:soc:fsl:qbman:qman.c: unsigned long jiffies value.

From Scott Wood <oss@buserror.net>
Newsgroups linux.kernel
Subject Re: [PATCH] drivers:soc:fsl:qbman:qman.c: unsigned long jiffies value.
Date 2017-04-30 01:40 +0200
Message-ID <tBK82-46a-3@gated-at.bofh.it> (permalink)
References <tBGxr-1U7-1@gated-at.bofh.it> <tBHtw-2sm-15@gated-at.bofh.it>
Organization NXP

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On Sat, 2017-04-29 at 22:43 +0200, Karim Eshapa wrote:
> unsigned long jiffies value sorry for that.

You mean unsigned long msecs?

> 
> Signed-off-by: Karim Eshapa <karim.eshapa@gmail.com>
> ---
>  drivers/soc/fsl/qbman/qman.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
> index e0df4d1..6e1a44a 100644
> --- a/drivers/soc/fsl/qbman/qman.c
> +++ b/drivers/soc/fsl/qbman/qman.c
> @@ -1084,7 +1084,7 @@ static int drain_mr_fqrni(struct qm_portal *p)
>  		 * entries well before the ring has been fully consumed, so
>  		 * we're being *really* paranoid here.
>  		 */
> -		unsigned int udel_time = jiffies_to_usecs(10000);
> +		unsigned long udel_time = jiffies_to_usecs(10000);
>  
>  		usleep_range(udel_time/2, udel_time);
>  		msg = qm_mr_current(p);

If unsigned int isn't big enough, then unsigned long won't be either on 32-
bit.  With such a long delay why not use msleep()?

As for the previous patch[1], you're halving the minimum timeout which may not
be correct.

For the NXP people: Is there *really* no better way to handle this than
waiting for so long?  Nothing that can be checked to exit the loop early (at
least, you could exit early if there is more work to do so only the final
iteration takes the full timeout)?  And why is the desired timeout specified
in jiffies, the duration of which can change based on kernel config and
doesn't reflect anything about the hardware?

-Scott

[1] When fixing a patch you've already posted that hasn't yet been applied,
send a replacement (v2) patch rather than a separate fix.

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Thread

[PATCH] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck hacking jiffies. Karim Eshapa <karim.eshapa@gmail.com> - 2017-04-29 21:50 +0200
  [PATCH] drivers:soc:fsl:qbman:qman.c: unsigned long jiffies value. Karim Eshapa <karim.eshapa@gmail.com> - 2017-04-29 22:50 +0200
    Re: [PATCH] drivers:soc:fsl:qbman:qman.c: unsigned long jiffies  value. Scott Wood <oss@buserror.net> - 2017-04-30 01:40 +0200
      RE:drivers:soc:fsl:qbman:qman.c: unsigned long jiffies value Karim Eshapa <karim.eshapa@gmail.com> - 2017-04-30 03:20 +0200
      [PATCH v2] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck hacking jiffies. Karim Eshapa <karim.eshapa@gmail.com> - 2017-05-04 07:00 +0200
        Re: [PATCH v2] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck  hacking jiffies. Scott Wood <oss@buserror.net> - 2017-05-04 23:10 +0200
          Re: [PATCH v2] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck  hacking jiffies. Roy Pledge <roy.pledge@nxp.com> - 2017-05-05 01:40 +0200
        RE: [PATCH v3] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck hacking jiffies. Karim Eshapa <karim.eshapa@gmail.com> - 2017-05-05 07:50 +0200
        RE: [PATCH v2] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck hacking jiffies. Karim Eshapa <karim.eshapa@gmail.com> - 2017-05-05 08:10 +0200
          Re: [PATCH v2] drivers:soc:fsl:qbman:qman.c: Sleep instead of stuck  hacking jiffies. Scott Wood <oss@buserror.net> - 2017-05-05 08:40 +0200

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