Re: [PATCH v7 0/5] Reset PCIe devices to address DMA problem on kdump with iommu

Thomas Renninger
2013-01-23T00:48:09Z

On Monday, January 21, 2013 10:11:04 AM Takao Indoh wrote:
> (2013/01/08 4:09), Thomas Renninger wrote:
...
> > I tried the provided patches first on 2.6.32, then I verfied with 3.8-rc2
> > and in both cases the disk is not detected anymore in
> > reset_devices (kexec'ed/kdump) case (but things work fine without these
> > patches).
>
> So the problem that the disk is not detected was caused by exactmap
> problem you guys are discussing? Or still not detected even if exactmap
> problem is fixed?
This problem is related to the 5 PCI resetting patches.
Dumping worked with a 2.6.32 and a 3.8-rc2 kernel, adding the PCI resetting
patches broke both. I first tried 2.6.32 and verified with 3.8-rc2 to make sure
I didn't mess up the backport adjustings of the patches to 2.6.32.

Unfortunately this Dell platform takes really long to boot.
I can give it the one or other test, but please do not bomb me with patches.

For info:
About the interrupt remapping error interrupt storm in kdump case I tried to
reproduce on this machine, but never could: The guys who saw that also cannot
reproduce this anymore.

Two ideas I had about this:
- As said already, (also) try to catch the error case and try to reset the
the device in AER/Specific iterrupt remapping error interrupt caught.
- Have a look at coreboot, these guys should know how to initialize the PCI
subsystem from scratch and might have some well tested PCI resetting
code in place already (no idea, just a thought).

Thomas