Re: [PATCH rc 1/2] iommu: Do not call drivers for empty gathers

Jason Gunthorpe
2026-03-31T19:58:55Z

On Tue, Mar 31, 2026 at 06:12:18PM +0100, Jon Hunter wrote:
> I noticed that a couple of our Tegra boards are no longer booting -next and
> bisect pointed to this commit. Reverting this does fix it.
>
> This is impacting our Tegra186 (using nvidia,tegra186-smmu compatible
> string) and Tegra194 (using nvidia,tegra194-smmu compatible string) boards.
> There is no specific crash I see, but the boards just appear to hang on
> boot. If you have any thoughts or things to try let me know.

Thanks, I was able to guess what the problem is:

https://patch.msgid.link/r/0-v1-664d3acaabb9+78b-iommu_gather_always_jgg@nvidia.com

Please let me know if it doesn't solve the problem

Jason