Hi Joerg, On 09/29/15 at 06:04pm, Joerg Roedel wrote: > On Thu, Sep 24, 2015 at 02:37:32PM +0800, Baoquan He wrote: > > Copy command buffer and event buffer from the old to kdump kernel. > > > > Still there are 2 problems: > > 1) Not very sure if this is necessary. If do not copy the old command buffer, and > > only set the newly allocated command buffer, is there anything wrong? > > No, there is no need to copy command and event buffers. Just make sure > they get re-initialized and flush all iommu caches after setting the new > device table. Thanks for your reviewing. I did a lot of tests. Seems that it doesn't matter with copy or without a copy. And it's also OK even completely ignore the command buffer and event log handling here. Thanks Baoquan