Re: [PATCH] pci: Disable master abort while waiting for an FLR to complete

[Brian Norris <briannorris@chromium.org>]

On Mon, May 15, 2017 at 02:00:33PM -0700, Brian Norris wrote:
> On Mon, May 15, 2017 at 12:48:30PM -0700, Alexander Duyck wrote:
> > On Mon, May 15, 2017 at 9:36 AM, Brian Norris <briannorris@chromium.org> wrote:
> > > So there may be several implementation bugs with RK3399. I don't know
> > > how much can be fixed on Rockchip's side, vs. how much can be
> > > accomodated in the PCI core.
> > 
> > This is the kind of thing we have PCIe quirks for if nothing else.
> > Odds are we should be able to work around it, it is just a matter of
> > knowing what all the quirks are.
> 
> Maybe your imagination for "quirks" isn't creative enough :)

BTW, I meant to note that people have gone to some extreme lengths to
handle buggy / quirky RCs. Look at drivers/pci/dwc/pci-imx6.c, which
hooks all the way into the core ARM exception handling just to mask
aborts! (See imx6q_pcie_abort_handler.) And they have some patches
intended to fix crashes in 4.12-rc1 to hook synchronous aborts to return
"all 1's". But that's extremely invasive and not very precise (I don't
think that even checks the difference between PCI-induced aborts and
other system aborts?). Probably not gonna fly on ARM64 either...

Brian

[1] [PATCH] PCI: imx6: fix downstream bus scanning
https://patchwork.ozlabs.org/patch/760748/