From: "Richard B. Johnson" <email@example.com> To: Kathy Frazier <firstname.lastname@example.org> Cc: Andi Kleen <email@example.com>, firstname.lastname@example.org Subject: RE: Interrupt doesn't make it to the 8259 on a ASUS P4PE mobo Date: Tue, 15 Jul 2003 11:31:17 -0400 (EDT) [thread overview] Message-ID: <Pine.LNX.4.53.0307151125400.15686@chaos> (raw) In-Reply-To: <PMEMILJKPKGMMELCJCIGOEKNCCAA.email@example.com> On Tue, 15 Jul 2003, Kathy Frazier wrote: > Thanks for your reply, Andi. > > >> We have a proprietary PCI board installed in a (UP) system with an ASUS > P4PE > >> motherboard (uses Intel 845PE chipset). This system is running Red Hat > 9.0 > > >Have you checked the 845 errata sheets on the Intel website? > >Perhaps it is some known hardware bug. > > >One thing you could try is to use Local APIC / IO APIC interrupt processing > >instead of 8259. > > Our hardware engineer has combed the Intel and ASUS websites, but found > nothing. I'll give the APIC a try and see if I get different results and > let you know. > > >> > >> /* start timer */ > >> dmatimer.expires = jiffies + 0.5*HZ; > > >That's a serious bug. You cannot use floating point in the kernel. > >It will corrupt the FP state of the user process. > > HZ on the INTEL platform is 100, so this should simply add 50 to the current > value of jiffies. Besides, assigning the value to the unsigned int field > (expires) will truncate it to an integer anyway. Is there a more > appropriate way to handle a short timeout? It will truncate it at runtime. I suggest dmatimer.expires = jiffies + HZ/2; Also, you you need to use the time_before() macro, like while ( time_before(jiffies, dmatimer.expires) ) do_something(); ... so you don't have a timer-wrap problem during jiffie rollover if you haven't already done so (I don't have your source here). > > Thanks, > Kathy Cheers, Dick Johnson Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips). Why is the government concerned about the lunatic fringe? Think about it.
next prev parent reply other threads:[~2003-07-15 15:17 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <firstname.lastname@example.org> 2003-07-15 16:14 ` Kathy Frazier 2003-07-15 15:31 ` Richard B. Johnson [this message] 2003-07-15 15:58 ` SCSI ATA driver in 2.4.22 ? Jeff Mock 2003-07-15 16:14 ` Jeff Garzik 2003-07-15 17:06 ` Interrupt doesn't make it to the 8259 on a ASUS P4PE mobo Brian Gerst 2003-07-15 17:43 ` Jamie Lokier 2003-07-15 17:59 ` Luciano Miguel Ferreira Rocha 2003-07-15 18:24 ` Brian Gerst 2003-07-15 18:44 ` Alan Cox 2003-07-15 19:44 ` Jamie Lokier 2003-07-20 21:04 ` Riley Williams 2003-07-20 22:25 ` Jeremy Fitzhardinge [not found] <Pine.LNX.4.53.0307141833190.4354@chaos> 2003-07-15 16:52 ` Kathy Frazier 2003-07-14 21:35 Kathy Frazier
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