Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sun, 9 Nov 2003 09:44:36 -0800 | From | Bob McElrath <> | Subject | Re: /dev/rtc on alpha |
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Ivan Kokshaysky [ink@jurassic.park.msu.ru] wrote: > On Sat, Nov 08, 2003 at 01:33:57PM -0800, Bob McElrath wrote: > > Why is the alpha kernel code grabbing the rtc interrupt? Is it possible > > it share its use with a user program? Would reprogramming the interrupt > > rate by a user program do violence to some internel kernel timing? > > On most Alphas RTC is the system timer (running at 1024 Hz). > So changing the interrupt rate from user space wouldn't be a good idea.
Then I propose CONFIG_RTC be set to "n" in the arch/alpha files, and the /dev/rtc driver be disabled on alpha. There seems to be confusion on this point in the config files. CONFIG_RTC is for the /dev/rtc driver.
Since the timer can only be set to powers of 2, it should be possible to simulate getting the interrupt by calling the rtc.c interrupt handler every 2^n interrupts...that way the user could program the timer for any interval less than 1024 Hz.
Cheers, Bob McElrath [Univ. of California at Davis, Department of Physics] [unhandled content-type:application/pgp-signature] | ![\](/images/icornerr.gif) |