dma-pool fixes

Amit Pundir amit.pundir at
Fri Jul 31 10:20:49 EDT 2020

On Fri, 31 Jul 2020 at 19:45, Nicolas Saenz Julienne
<nsaenzjulienne at> 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:
> 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.

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.

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