Messages in this thread | | | Date | Fri, 9 Sep 2022 14:47:19 +0100 | Subject | Re: [PATCH v5 2/2] PCI: dwc: Add support for 64-bit MSI target address | From | Robin Murphy <> |
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On 2022-09-09 14:29, Christoph Hellwig wrote: > On Thu, Aug 25, 2022 at 06:50:25PM +0000, Will McVicker wrote: >> Since not all devices require a 32-bit MSI address, add support to the >> PCIe host driver to allow setting the DMA mask to 64-bits if the 32-bit >> allocation fails. This allows kernels to disable ZONE_DMA32 and bounce >> buffering (swiotlb) without risking not being able to get a 32-bit address >> during DMA allocation. > > Umm. You can't just disable ZONE_DMA32. Linux absolutely requires a > 32-bit dma mask to work, it is in fact the implicit default.
Eh, it's behind CONFIG_EXPERT, which makes it enough of a "I think I know what I'm doing and accept responsibility for picking up the pieces if it breaks" thing.
Robin.
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