Re: [PATCH 8/8] habanalabs: enable 64-bit DMA mask in POWER9

From: Christoph Hellwig
Date: Tue Jun 11 2019 - 11:17:17 EST

On Tue, Jun 11, 2019 at 08:50:45AM +0300, Oded Gabbay wrote:
> 2. The pci_set_dma_mask() is a generic Linux kernel call, so the driver
> can't tell why it got an error when it tried to set the DMA mask to 48
> bits. And upon such failure, the driver must fall-back to set the mask
> to 32 bits.

In the current kernel pci_set_dma_mask only fails if the DMA mask is
to small to be supportable at all. So you very obviously did not
actually test this against mainline.