[RFC][PATCH] Reset PCIe devices to address DMA problem on kdump with iommu

Vivek Goyal vgoyal at redhat.com
Tue Sep 11 10:43:23 EDT 2012

On Tue, Sep 11, 2012 at 07:32:35PM +0900, Takao Indoh wrote:

> I'll post new patch which clears bus master bit and resets devices in
> second kernel.
> As to the boot parameter to enable this function, you suggested using
> reset_devices. I found that on a certain platform resetting devices
> caused PCIe error due to a hardware bug. Therefore I think we need
> new parameter apart from reset_devices to disable this function on
> such a machine.

Can you explain a bit more how the error happens. I still don't think
that because of a bug in a platform somewhere we should be introducing
a separate command line parameter and not reuse the exisiting one. Also
you have not explained what's the bug and how a new parameter will 
avoid the bug.


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