Crud, my poor gmail skills dropped lkml on the CC list for this one.
On 2/23/07, john stultz <[EMAIL PROTECTED]> wrote:
On 2/23/07, David Miller <[EMAIL PROTECTED]> wrote: > While probeing PLL information via radeon_get_pllinfo(), it does a > "gettimeofday(); do_something(); gettimeofday();" type sequence > explicitly with interrupts disabled, so ends up with a zero > measurement which then results in a bunch of divisions by zero. This is at module init time? If so I just sent out a patch yesterday to akpm that might help this issue (assuming other clocksources are available on the hardware). > We should decide whether gettimeofday() can be expected to advance with > interrupts disabled, or that clocksource_jiffies is simply invalid because > of this behavior. Some arches have no fine-grained timekeeping, so I don't think it can always be assumed, but where hardware is available it should function. It should be noted that with older kernels, if interrupts were disabled right before a tick, it would be possible that gettimeofday()'s limiting code would cause time to stop advancing until interrupts were re-enabled. So theoretically its not really a new issue. The timekeeping_is_continuous() function could be used to flag this sort of "software driven vs continuous" clocksource cases. thanks -john
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