Linux-kernel mailing list archive 2000-29,: Re: APIC and edge triggered vs level triggered

# Re: APIC and edge triggered vs level triggered

Miquel van Smoorenburg (miquels@cistron.nl)
17 Jul 2000 11:32:17 GMT

- Messages sorted by: [ date ][ thread ][ subject ][ author ]
- Next message: Stephen C. Tweedie: "Re: [linuxperf] Mini-howto: High performance large Ext2fs filesystems [[BETA]]"
- Previous message: Tim Waugh: "Re: 2.4.0-test4 breaks parport printing"

In article <cistron.8ko68e$j0$1@enterprise.cistron.net>,
Miquel van Smoorenburg <miquels@cistron.nl> wrote:
>AMI Megarum II board w/ 2xPIII/450 1 GB RAM, dual symbios onboard SCSI
>1 9 GB system disk on scsi0, 4 18 GB spool disks on scsi1
>Linux 2.2.17pre11
>
>After 5-15 minutes, the system hung. The symbios chipset stopped to
>deliver interrupts. When I posted this to linux-scsi, Gerard Roudier
>said that it was logical that the system wasn't stable: APIC PCI
>interrupts have to be level triggered and not edge triggered, while
>the output from /proc/interrupts said:
>
> CPU0 CPU1
> 10: 41954 47456 IO-APIC-edge sym53c8xx
> 15: 1684 3355 IO-APIC-edge sym53c8xx
>
>However, in the AMI BIOS (or the scsi bios) there is no way to adjust
>this. The BIOS sets the interrupts to edge triggered, and that's it.

I found the solution myself this weekend.

It appears that the BIOS reports the interrupts as edge triggered,
while in reality they are level triggered. So we need a way to
override the information from the BIOS.

Jos van de Ven posted such a patch on the linux-smp mailinglist
about a year ago. Fortunately the patch still applies and solves my
problem completely.

See http://marc.theaimsgroup.com/?l=linux-smp&m=93143486926833&w=2
for Jos' posting and the patch.

Mike.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

- Next message: Stephen C. Tweedie: "Re: [linuxperf] Mini-howto: High performance large Ext2fs filesystems [[BETA]]"
- Previous message: Tim Waugh: "Re: 2.4.0-test4 breaks parport printing"