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    SubjectRe: [DVB patch 51/54] ttpci: av7110: RC5+ remote control support
    On 9/4/05, Johannes Stezenbach <js@linuxtv.org> wrote:
    > On Sun, Sep 04, 2005 Nish Aravamudan wrote:
    > > On 9/4/05, Johannes Stezenbach <js@linuxtv.org> wrote:
    > > > On Sun, Sep 04, 2005 Nish Aravamudan wrote:
    > > > > On 9/4/05, Johannes Stezenbach <js@linuxtv.org> wrote:
    > > > > >
    > > > > > -#define UP_TIMEOUT (HZ/4)
    > > > > > +#define UP_TIMEOUT (HZ*7/25)
    > > > >
    > > > > #define UP_TIMEOUT msecs_to_jiffies(280)
    > > > > #define UP_TIMEOUT (7*msecs_to_jiffies(40)
    > > >
    > > > I agree it's nicer to read, but AFAIK not required for correctness?
    > > > If so, then we'll fix those up in linuxtv.org CVS and submit
    > > > cleanup patches later.
    > >
    > > Yeah, it's correct with the three current values of HZ (100, 250 and
    > > 1000), but if you try a not-so-clean value (like Con did with 864, or
    > > something), you might run into rounding issues. msecs_to_jiffies()
    > > should take care of them (or will be a single point to do so
    > > eventually).
    >
    > Well, if msecs_to_jiffies() is the new way of specifying timeouts
    > we'd have a lot more to fix up in our tree. But something like
    > a remote control key-up timeout doesn't need much precision.
    > Generally I see nothing wrong with HZ/4, but something like
    > HZ*20/1000 could be problematic with small or odd HZ values.

    This discussion comes up every time ;) HZ/4 rounds incorrectly
    (depends on your perspective, I guess) with HZ=250.

    > Agreed? Or is it desired that people generally use msecs_to_jiffies()?

    I agree, generally it's ok, as timeouts aren't meant to be precise. I,
    personally, am converting code over to msecs_to_jiffies() as I come to
    it, just so that the conversions are consistent (a number in the tree
    were not, not that yours are) and basically self-commented. And, like
    I mentioned, they are automatically rounded correctly with "strange"
    values of HZ.

    The changes I mentioned in your patchset are generally not critical,
    but just comments and my own preferences.

    Thanks,
    Nish
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