Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds

["Richard W.M. Jones" <rjones@redhat.com>]

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On Mon, Aug 03, 2015 at 03:52:28PM +0200, Laurent Vivier wrote:
> +    /* A 33 Mhz clock gives a 30 ns tick,
> +     * convert timeout from ticks to ns
>       */
> -    timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000);
> +    timeout *= 30;

I see that you've just posted a v2 of this patch.  However here are
the results of testing the above version.  I used the attached test
script which automates things, mostly.

All times are in seconds.

  Requested timeout       Observed timeout
         60                     58
        120                    120
        250                    249
        270                    271
        500                    501  [note 1]
        520                    522
       1010                   1016
       1030                   1035
       2046                   2058
       2500  ioctl: WDIOC_SETTIMEOUT: error setting timeout: Invalid argument
                              [note 2]

[note 1] I'm not worried about the timeout being off by a few seconds,
as that could easily be caused by inaccuracies in the test framework.

[note 2] Maximum setting for i6300esb Linux driver is 2046, see
linux.git/drivers/watchdog/i6300esb.c but note that the printed
messages in the driver relating to the range of the timeout are not
accurate.

This patch looks good to me.  I will test the v2 patch shortly.

Rich.

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