Re: [PATCH 2/2] arm64: dts: qcom: hamoa: Reserve low IOVA range for Iris

[Daniel J Blueman]

On Thu, 4 Jun 2026 at 14:39, Vikash Garodia
<vikash.garodia@xxxxxxxxxxxxxxxx> wrote:
> On 6/2/2026 9:05 PM, Daniel J Blueman wrote:
> > On Tue, 2 Jun 2026 at 18:27, Bryan O'Donoghue <bod@xxxxxxxxxx> wrote:
> >> On 01/06/2026 05:13, Daniel J Blueman wrote:
> >>> On X1-family hamoa platforms, Iris DMA below IOVA 0x25800000 (600MB)
> >>> triggers unhandled SMMU page faults
> >>
> >> How do we know that is a correct address - does it come from qcom
> >> documentation or trial and error ?
> >
> > @Vikash, beyond your comment I linked in the patch [1] kindly cite a
> > source for the different stream-ID <600MB behaviour, and share
> > specifics, eg if silicon, firmware, or driver and constraint, defect
> > or otherwise, so I can include a definitive description.
> >
> > Also good to know if my workaround is good for long-term, or on the
> > other hand handling streams <600MB is important/useful.
>
> Thanks Daniel for raising this patch. Did you also try the memory fix i
> mentioned in the bug [1] discussion ?

With this patch, my Lenovo Slim 7x spontaneously rebooted after
opening 3 tabs of https://ui.com rather than 1 without it. No
crash/reboot is reproducible with the patch I proposed.

> 0-600MB range, VPU hardware would reserve this to generate different
> stream-IDs primarily for internal (non-pixel) buffers.

Thanks for the clearer description; I'll respin my patch with this and
the DT fixes shortly to get the X1 user experience under control until
a real fix.

@all I appreciate the ideas and discussion already ensured!

Dan
-- 
Daniel J Blueman