Re: [PATCH v2 0/2] Reset PCIe devices to address DMA problem on kdumpwith iommu

From: Takao Indoh
Date: Tue Oct 02 2012 - 21:03:20 EST


(2012/10/03 4:37), Andi Kleen wrote:
Takao Indoh <indou.takao@xxxxxxxxxxxxxx> writes:

These patches reset PCIe devices at boot time to address DMA problem on
kdump with iommu. When "reset_devices" is specified, a hot reset is
triggered on each PCIe root port and downstream port to reset its
downstream endpoint.

Great. I've been pondering this for a long time, but you did finally
implement it. I hope this will make kdump a lot more reliable at least
on the systems that support per port reset.

Actually I got the idea of this patch from your comment below;-)
http://permalink.gmane.org/gmane.linux.network/162414


Now the only question is: why make it a option and not default?

Except kdump I don't know the situation where this reset is useful, so I
introduced it as option so that it works only during kdump.

Thanks,
Takao Indoh

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