On Wed, 2018-08-29 at 18:30 -0500, Scott Wood wrote:

On Tue, 2018-08-28 at 20:13 +0100, Darren Stevens wrote:

quoted

Hello Scott

On 27/08/2018, Scott Wood wrote:

quoted

On Mon, 2018-08-27 at 20:15 +0200, Christian Zigotzky wrote:

quoted

Hello,

Our users tested the RC1 of kernel 4.19 on their P5020 boards today.
Unfortunately the USB bug still exists. With mem values bigger than
4096M,
the USB mouse and keyboard doesn't work. With the bootarg mem=4096M,
the
USB
devices work without any problems. Please compile the RC1 and test it
on
your P5020 board. There is a problem with the memory management since
22/08/18. 

I just tested 4.19-rc1 on a T4240 and got a similar problem with
MMC.  MMC
and
USB on these chips both have a 32-bit DMA limitation.  I'll look into
it.

I've run a bisect locally on my system and found the following bad commit:

# first bad commit: [1b1eeca7e4c19fa76d409d4c7b338dba21f2df45] init: allow
initcall tables to be emitted using relative references

I can't see why this would fail though, and it only seems to affect fsl
machines, and on mine it killed the onboard sata as well.

Hope this helps.

The patch is changing the order of initcalls.  swiotlb_setup_bus_notifier()
and corenet_gen_publish_devices() are both machine_arch_initcall(), and if
the
latter happens before the former, then the bus notifier gets missed and
swiotlb doesn't get used.

While it would be nice to fix this ordering dependency at some point, the
change was reverted on PPC by commit ff69279a44e9ba876466 ("powerpc: disable
support for relative ksymtab references").

-Scott