On Tuesday 28 September 2010 08:27:21 Ignacy Gawedzki wrote: > On Tue, Sep 28, 2010 at 01:28:22AM +0200, thus spake Christian Lamparter: > > On Tuesday 28 September 2010 01:01:37 Ignacy Gawedzki wrote: > > > On Mon, Sep 27, 2010 at 07:36:21PM +0200, thus spake Christian Lamparter: > > > > Sure, but why when you have a monotonic 40 MHz timer? > > > > > > Glad to know there is such a thing, then. =) > > or was it 80Mhz? Nevermind, the docs are not very specific. > > AFAICT there's a constant in timer.h : > > #define AR9170_TICKS_PER_MICROSECOND 80 it is supposed to be 25 ns clock counter > but there's also that clock_set() function that seems to be setting the clock > up with different frequencies, but I supppose that's a different thing. clock_set sets the CPUs clock, which has an effect on timer0-3 but not on the clock source. > > > I just tried the whole setup with the latest wireless-testing sources and your > > > patch on the firmware. So far, so good, the problems I had previously are not > > > showing up. I'm now just adapting your proposition to support rollover and > > > conversion of the measurement to nanoseconds. > > Rollover checks? Can you please tell me where you exactly see a potential > > rollover problem in the proposal? > > Well, what I meant was to support the case when the clock ticks counter wraps > around. Supposing there are 40e6 ticks per second, 2^32 ticks run out in less > than 108 seconds, or maybe I'm missing something here. yes, "MAC RESET" and carl9170_tx_janitor. A frame can't be delayed for more than 6 second. > I then need to consider the case where comp_tsf ends up not being larger > than tsfl. Since > we're dealing with unsigned ints, in this case the > simple difference would end up being something rather large. :/ Too much bad literature. Give it a try, set comp_tsfl = 0x10 and super->s.tsfl = 0xfffff000. then comp_tsfl - super->s.tsfl equals to 0x10 - 0xfffff000, which on a 32-bit arch gives you 0x00001010 (+ carry/borrow) Regards, Chr -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
