dma-pool fixes

[Amit Pundir]

On Fri, 31 Jul 2020 at 19:45, Nicolas Saenz Julienne
<nsaenzjulienne at suse.de> wrote:
>
> On Fri, 2020-07-31 at 16:47 +0530, Amit Pundir wrote:
> > On Fri, 31 Jul 2020 at 16:17, Nicolas Saenz Julienne
>
> [...]
>
> > > Ok, so lets see who's doing what and with what constraints:
> >
> > Here is the relevant dmesg log: https://pastebin.ubuntu.com/p/dh3pPnxS2v/
>
> Sadly nothing out of the ordinary, looks reasonable.
>
> I have an idea, I've been going over the downstream device tree and it seems
> the reserved-memory entries, specially the ones marked with 'no-map' don't
> fully match what we have upstream. On top of that all these reserved areas seem
> to fall into ZONE_DMA.
>
> So, what could be happening is that, while allocating pages for the ZONE_DMA
> atomic pool, something in the page allocator is either writing/mapping into a
> reserved area triggering some kind of fault.
>
> Amir, could you go over the no-map reserved-memory entries in the downstream
> device-tree, both in 'beryllium-*.dtsi' (I think those are the relevant ones)
> and 'sdm845.dtsi'[1], and make sure they match what you are using. If not just
> edit them in and see if it helps. If you need any help with that I'll be happy
> to give you a hand.

Thank you for the pointers. I'll try to match my dts' reserved-memory
entries with the downstream dts. I'll let you know how it goes.

Regards,
Amit Pundir

>
> Regards,
> Nicolas
>
> [1] You could also extract the device tree from a device running with the
>     downstream kernel, whatever is easier for you.
>