Date: Fri, 27 Feb 2009 15:02:36 -0500 From: John Baldwin <jhb@freebsd.org> To: Robert Noland <rnoland@freebsd.org> Cc: freebsd-current@freebsd.org, Sergey G Nasonov <snasonov@bcc.ru> Subject: Re: Interrupt stom on cardbus device Message-ID: <200902271502.37051.jhb@freebsd.org> In-Reply-To: <1235761864.1289.54.camel@widget.2hip.net> References: <200902271730.07660.snasonov@bcc.ru> <200902271403.46828.jhb@freebsd.org> <1235761864.1289.54.camel@widget.2hip.net>
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On Friday 27 February 2009 2:11:04 pm Robert Noland wrote: > On Fri, 2009-02-27 at 14:03 -0500, John Baldwin wrote: > > On Friday 27 February 2009 1:50:28 pm Robert Noland wrote: > > > On Fri, 2009-02-27 at 12:08 -0500, John Baldwin wrote: > > > > On Friday 27 February 2009 9:30:06 am Sergey G Nasonov wrote: > > > > > Hello all, > > > > > I have get an issue after recent kernel recompile. > > > > > The problem appears after switch from X to text console and back to X11. > > > > > After that vmstat -i show an interrupt storm on cardbus device: > > > > > > > > > > > vmstat -i > > > > > interrupt total rate > > > > > irq1: atkbd0 6483 3 > > > > > irq9: acpi0 3236 1 > > > > > irq12: psm0 347988 167 > > > > > irq14: ata0 16431 7 > > > > > irq16: cbb0 uhci2+ 13624982 6556 > > > > > irq20: uhci0 14 0 > > > > > irq22: ehci0 2 0 > > > > > cpu0: timer 4154687 1999 > > > > > irq256: em0 53736 25 > > > > > irq257: hdac0 5797 2 > > > > > cpu1: timer 4153683 1998 > > > > > irq258: vgapci0 235585 113 > > > > > Total 22602624 10877 > > > > > > > > > > I suppose that the issue related with the latest MSI interrupt > > > > > handler changes for intel graphics chipset. My laptop has i965GM. > > > > > pciconf -lv: > > > > > > > > > > vgapci0@pci0:0:2:0: class=0x030000 card=0x20b517aa chip=0x2a028086 > > > > > rev=0x0c hdr=0x00 > > > > > vendor = 'Intel Corporation' > > > > > device = 'Mobile 965 Express Integrated Graphics Controller' > > > > > class = display > > > > > subclass = VGA > > > > > > > > > > When I added my device to drm_msi_blacklist and recompile drm modules > > the > > > > > problem disappear. > > > > > Is it possible to resolve this problem without moving the device to the > > > > > drm_msi_blacklist? > > > > > I can test any patches or provide additional detail if it is required. > > > > > Thanks. > > > > > > > > It seems the device is still interrupting on its INTx line perhaps in > > addition > > > > to the MSI interrupts. > > > > > > Hrm, I did most all of that development on a 965gm. When you VT switch, > > > the irq handler gets uninstalled and reinstalled when you return to X. > > > There was an eratta on the 965gm suggesting that msi didn't work right, > > > but I was never able to produce the issue. Intel was having major > > > issues with this on linux and I finally convinced them to turn msi back > > > on. My irq handler and Eric's are very similar, so I'm not sure what > > > could be going on here. > > > > > > There is however an issue with vblanks that might be related. Could you > > > try http://people.freebsd.org/~rnoland/drm-move_vblank_init.patch and > > > see if that helps? > > > > In this case the issue isn't that MSI isn't working I think, but that the > > hardware is sending interrupts via both routes (MSI and INTx). If that > > happens, then you will see an interrupt storm on the INTx line, but FreeBSD > > will only notice if another device is sharing the same IRQ line. So if your > > test machine has vgapci0 on irq 22 and you have no other devices on IRQ 22, > > then the storm would go unnoticed. This is most likely a chip bug (unless > > the driver has to explicitly disable INTx interrupts when using MSI). It > > would probably be a good idea to add a hw.drm.msi_enable tunable (or > > hw.drm.msi) that people can use to disable MSI perhaps. > > Ok, I do have docs on the 965, so I'll look at this. The linux version > does not do this, unless the OS does it in the background somewhere. Perhaps Eric can help to answer a question about the hardware in this case. > I thought about adding a tuneable, but I have to figure out how that > works first... ;) You can basically do something like this: int drm_msi = 1; /* Enable by default. */ TUNABLE_INT("hw.drm.msi", &drm_msi); And later don't enable msi if it is zero. -- John Baldwin
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