Use of pci_map_page in nouveau, radeon TTM.

Jerome, Konrad

Forgive an ignorant question, but it appears like both Nouveau and Radeon may use pci_map_page() when populating TTMs on pages obtained using the ordinary (not DMA pool). These pages will, if I understand things correctly, not be pages allocated with DMA_ALLOC_COHERENT.

From what I understand, at least for the corresponding dma_map_page() it's illegal for the CPU to access these pages without calling dma_sync_xx_for_cpu(). And before the device is allowed to access them again, you need to call dma_sync_xx_for_device(). So mapping for PCI really invalidates the TTM interleaved CPU / device access model.

Or did I miss something here?

Thanks, Thomas