Interrupt stom on cardbus device
rnoland at FreeBSD.org
Fri Feb 27 11:11:13 PST 2009
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 at 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
> > > > 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
> > > 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.
I thought about adding a tuneable, but I have to figure out how that
works first... ;)
Robert Noland <rnoland at FreeBSD.org>
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