Date: Thu, 27 Sep 2007 14:28:02 +0200 From: Gary Jennejohn <gary.jennejohn@freenet.de> To: freebsd-current@freebsd.org Cc: bruce@cran.org.uk Subject: Re: Interrupt storm on ahc0 when drm module is loaded Message-ID: <20070927142802.1ae6541d@peedub.jennejohn.org> In-Reply-To: <20070926113643.GA21109@muon.bluestop.org> References: <20070926113643.GA21109@muon.bluestop.org>
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On Wed, 26 Sep 2007 12:36:44 +0100 bruce@cran.org.uk wrote: > I've come some sort of conflict between the drm and ahc drivers: > whenever drm is loaded I get an interrupt storm on ahc0. My system is: > > 7.0-CURRENT #0: Tue Sep 25 18:08:50 BST 2007 > /usr/obj/usr/src/sys/GENERIC i386 > > I'm running Xorg 7.3 > > ahc0: <Adaptec 19160B Ultra160 SCSI adapter> port 0xdc00-0xdcff mem > 0xd9200000-0xd9200fff irq 16 at device 9.0 on pci0 > ahc0: [ITHREAD] > da0 at ahc0 bus 0 target 6 lun 0 > > drm0: <Matrox G200 (AGP)> on vgapci0 > info: [drm] AGP at 0xd0000000 64MB > info: [drm] Initialized mga 3.2.2 20060319 > info: [drm] Initialized card for AGP DMA > drm0: [ITHREAD] > > vmstat -i: > interrupt total rate > irq1: atkbd0 4036 0 > irq14: ata0 58 0 > irq16: ahc0 15004943 2824 > irq19: fxp0 40961 7 > cpu0: timer 10624196 1999 > cpu1: timer 10606936 1996 > Total 36281130 6828 > > Over time the rate for ahc0 grows until I get the "Interrupt storm > detected: throttling irq16" messages. I can trigger the problem by > changing the default colour depth to 16 bits in my xorg.conf file: this > enables the drm module to load and immediately the interrupt rate starts > to climb. > Have you looked at disabling interrupts for VGA in your BIOS (if possible)? Don't know what effect this would have on X11's performance. You could also try a different PCI slot. An unrelated question. I also have a 19160 but the SCSI BIOS never shows up at boot time so I can't boot from it. Did you ever see anything like that? -- Gary Jennejohn
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