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

[Val Packett]

On 6/2/26 7:26 AM, Bryan O'Donoghue 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 ? 


If you follow the Link:, you can see that it does come from qcom..

https://github.com/qualcomm-linux/kernel-topics/issues/1157#issuecomment-4458933574

This series is basically a "hotfix" version of a more complicated series:

https://lore.kernel.org/linux-media/20250627-video_cb-v3-0-51e18c0ffbce@xxxxxxxxxxx/

that introduced an extra subnode that let the driver only use that 
restricted IOVA range for non-pixel buffers (only those actually need 
the restriction) but that resulted in a very long discussion and was 
kinda shelved because of that.. x_x


~val