On Thu, Dec 15, 2022 at 02:53:03AM +0300, Serge Semin wrote: > DW PCIe Root Ports and End-points can be equipped with the DW eDMA engine. > In that case it is critical to have the platform device pre-initialized > with a valid DMA-mask so the drivers using the eDMA-engine would be able > to allocate the DMA-able buffers. The MSI-capable data requires to be > allocated from the lowest 4GB region. Since that procedure implies the > DMA-mask change we need to restore the mask set by the low-level drivers > after the MSI-data allocation is done. You can't change the DMA mask when there are existing allocations.
