Re: [PATCH RFC] powerpc/kernel: Don't check for dev->dma_mask in fsl_set_dma_mask

On Sun, 2018-09-02 at 12:30 +0100, Darren Stevens wrote:

To enable use of dma to all ram on a corenet generic system, we add the
function fsl_pci_dma_set_mask, and link it into the ppc.md structure.

But this function checks for the presence of dev->dma_mask and dma_ops
at entry, and fails if one or other are missing. Powerpc's dma_set_mask 
(which it is called from) doesn't check this until after it has set the 
dma_mask for pci devs,

It's checking whether the dma_mask pointer is valid before storing into that
pointer.  The generic ppc dma_set_mask does check this before storing into it.
   All it does before that check is to look for an alternative dma_set_mask
implementation.

Is the test failing on dma_mask or dma_supported?  If the latter, what are the
dma ops set to?

Can you check whether the problem still exists after commit
ff69279a44e9ba876466 ("powerpc: disable support for relative ksymtab
references")?

-Scott