RE: Interrupt stom on cardbus device

On Sat, 2009-02-28 at 12:02 +0300, Nasonov Sergey wrote:
> > -----Original Message-----
> > From: Robert Noland [mailto:rnoland_at_FreeBSD.org]
> > Sent: Saturday, February 28, 2009 2:44 AM
> > To: Nasonov Sergey
> > Cc: John Baldwin; freebsd-current_at_freebsd.org
> > Subject: RE: Interrupt stom on cardbus device
> > 
> > On Sat, 2009-02-28 at 00:09 +0300, Nasonov Sergey wrote:
> > > > -----Original Message-----
> > > > From: John Baldwin [mailto:jhb_at_freebsd.org]
> > > > Sent: Friday, February 27, 2009 10:04 PM
> > > > To: Robert Noland
> > > > Cc: freebsd-current_at_freebsd.org; Nasonov Sergey
> > > > Subject: Re: Interrupt stom on cardbus device
> > > >
> > > > 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
> > > > 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?
> > >
> > > Ok, I tried it but result the same (problem not resolved).
> > > Can I check anything else?
> > 
> > Ok, new patch... It is looking like we should actually deal with this
> in
> > the pci code, rather than drm, but let's try this patch and see if it
> > fixes the issue.  Note that we are looking for interrupts to still
> work
> > (the msi ones anyway) and to not see the INTx ones.
> > 
> > http://people.freebsd.org/~rnoland/i915_disable_INTx.patch
> > 
> > robert.
> 
> Unfortunately, your patch doesn't help. Maybe INTx is still enabled? But
> I think the problem somewhere herein.
> I compile DRM modules with DRM_DEBUG, but output is very large and find
> within it anything useful is hard. 

Hrm, the intel driver is very noisy.  If the problem really is INTx,
then the drm debugging won't know anything about that.  Could you try
that patch that I posted later, without this patch to i915.  I've looked
over the linux pci code and they do disable INTx when enabling MSI.

I stuck the patch up as
http://people.freebsd.org/~rnoland/pci_disable_intx.patch

robert.

> > > Thanks.
> > > >
> > > > 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.
> > > >
> > > > --
> > > > John Baldwin
> > --
> > Robert Noland <rnoland_at_FreeBSD.org>
> > FreeBSD
-- 
Robert Noland <rnoland_at_FreeBSD.org>
FreeBSD