On 3/28/20 10:37 AM, Alan Stern wrote:
On Fri, 27 Mar 2020, John Donnelly wrote:
Hi,
I am seeing this WARNING event with iommu=off when booting a DL380
server with a 5.4.17 kernel.
...
The end result is this USB port is not configured when
dma_direct_map_page() is called and it returns return
DMA_MAPPING_ERROR;
When I boot the server with iommu=on I don’t see this sequence :
...
On an older kernel 5.3. flavor I am not seeing this behavior, and the usbhib devices appear as expected :
I forgot to mention: Since you have one kernel where the WARNING occurs
and one where it doesn't, you can use bisection to find the commit that
was responsible for the change in behavior. If you care to go to the
trouble...
Alan Stern
Hi.
Yes that is the plan ! It may take awhile.
--
Thank You,
John
