Re: [PATCH v4 3/3] mmc: sdhci-pci: Do not set DMA mask in enable_dma()

From: Adrian Hunter
Date: Mon Mar 14 2016 - 09:04:24 EST

On 14/03/16 05:15, Alexandre Courbot wrote:
> On Tue, Mar 8, 2016 at 10:18 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>> On 07/03/16 04:07, Alexandre Courbot wrote:
>>> DMA mask will already be set by sdhci_set_dma_mask(), which
>>> is equivalent to the removed code since pci_set_dma_mask()
>>> expands to its DMA-API counterpart.
>>> There should also be no reason to set the DMA mask after probe.
>> Let's run that by the PCI mailing list just to be sure. The patches for
>> reference:
>> change the sdhci-pci driver to set the DMA mask once during probe instead of
>> every time during resume. Is there any reason a PCI device driver might
>> need to set the DMA mask every time during resume?
> Not seeing much reaction for this patchset. PCI being the only
> possible point of contention, can we maybe roll it into -next and see
> what happens?


Rafael, can you offer any thoughts on this:

PCI drivers that want to use DMA might call pci_set_master() in the pm
resume callback. Some drivers (like sdhci-pci) also, presumably out of
convenience, set the DMA mask at the same time. The question is: is it OK
instead to set the DMA mask just once during probe, or is there some other
reason the DMA mask needs to be set every time during resume?