Russell Johnson wrote:
I tested (and intended) the patch for MSI (w/o maskbits), not MSI-X.
What e1000 chip are you using exactly? Easiest way to tell is by using
'/sbin/lspci'. I may be able to help you out with MSI-X as well, but in
that case, I have no hardware platform to test on.
You can check whether or not MSI is actually being used by doing
'/sbin/lspci -v' and look for the Capability: Message Signalled
Interrupt. When the driver is running in MSI mode, it should read
'Enable+' instead of 'Enable-'.
This e1000 chip actually doesn't have MSI support. I had assumed that since
the e1000 driver caused the hanging and disabling MSI in the kernel caused
the hang to go away that the problem was MSI in the e1000. The e1000 driver
only enables MSI on newer chips than what are in the Dell 28xx machines.
Same problem here actually; the e1000 driver attempts to enable MSI routing for
recent adapters (i82547 rev. #2, if I read this code correctly) due to bugs in
older revisions. Unfortunately, the dual Xeon I've been using to check for
CONFIG_PCI_MSI has an older adapter, so the routing is still done by the IO-APIC,
and the bug does not trigger.
As it's a Dell, I assume there's two Intel Penium CPU's
inside. Are you running with SMP enabled ?
SMP is enabled.
The local (internal) CPU APIC hasn't been informed that the interrupt
has been dealt with and it will therefore allow no other interrupts
anymore to arrive in the CPU (including your keyboard's).
In fact, your CPU is idle.
I have used a PCI analyzer to see infinite loops on this machine for past
similar kernel issues and assumed it would be the same due to the symptoms.
When I build a kernel with Adeos but disable MSI then the
system works fine for the most part. There is one scenario
where the system will still hang
doing disk and network accesses under a moderate load of I/O.
Hm. That may indicate another issue.
Indeed. This behaviour has not been reported yet with patches
from the Adeos I-pipe series. Does it also happen with SMP
disabled, or Hyperthreading disabled?
It did happen with SMP disabled and I have always left hyperthreading
disabled because it is my understanding that hyperthreading is not supported
by the adeos patch.
Adeos should not have any problem with HT; actually it has no impact on the
interrupt sub-system it deals with, we just happen to see multiple CPUs, which is
common case handled by the SMP support.
Try upgrading the kernel. The kernel usually comes with updated drivers
as well. Currently I'm running 2.6.16-rc2, which I had to patch manually
for Adeos (about 3 'hunks' from the 2.6.15-i386-1.2-00 patch didn't
apply properly). By using 2.6.16-rc2, I got much better Intel
(especially i865 graphics) chipset support than 2.6.15. Note, however,
that I did the bug fixing in this thread on a plain 2.6.15, though (and
the msi.c code is nearly identical).
I would recommend upgrading to 2.6.15 with the latest Adeos patch and
try to get a stable system before enabling MSI.
In short, MSI doesn't seem to have been my issue. I now have a more stable
kernel. Apparently this system had some other faults with the specific
configuration options I was using. I had to patch to the 126.96.36.199 level
(was at .4) and change some of the options in my .config. Specifically, I
had to leave ACPI enabled (I had disabled as a test a while back). With
ACPI disabled, the machine would still hang if the USB was disabled in the
You might want to try booting with acpi=ht, so that the ACPI kitchen sink is
warmed up far enough to enumerate LAPICs but not more.
After learning how to check for MSI, no devices in my system seem to
actually be using MSI. The code patches you provided were never actually
executed. Time will tell if my system is stable.
Thanks for your help!
You are welcome.
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