On 31 October 2016 at 22:56, Florian Fainelli [off-list ref] wrote:

On 10/31/2016 02:46 PM, Scott Branden wrote:

quoted

A problem with reintroducing this change is that all imprecise data
aborts are ignored, not just PCI.  So if you don't actually use PCI in
your system and want to debug other aborts you are unable to.  I don't
know if we care about such situation.

Considering that any abort is pretty much fatal, the options are:

- update the freaking bootloader to a version where there are no such
aborts generated, not an option on consumer devices, unclear which
version (if any) fixes that

- fixups the aborts externally, via a boot wrapper, which is going to
take some time to develop, causes additional burden on the distributors
to provide instructions/build images on how to do it

In practice updating bootloader is not possible (as you noticed) but I
don't think it's even possible to fix this problem at bootloader /
extra loader level. If this was a matter of hardware setup, we could
handle it in kernel as well I believe. Ray actually verified it's
controller limitation on Northstar platform.
It sounds a bit like you're thinking about MMU and Dcache Northstar
problem when writing that e-mail.

- fixups the aborts in the kernel, irrespective of where they come from,
simple and easy

- fixups the aborts in the kernel, look where they come from, by using
some bit of magic, looking at PCIe registers and whatnot (provided that
is even possible), not too hard, but can take a while, and is error prone

I can certainly advocate that option 3 is the one that gives a working
device, and this is what matters from a distribution perspective like
LEDE/OpenWrt.

-- 
Rafa?