On Wed, Jan 30, 2019 at 03:01:54PM +0800, Hanjun Guo wrote: > This is the RFC version, I'm not sure this is the best solution, > comments are warmly welcomed. > > Thanks > Hanjun > > drivers/usb/core/hcd-pci.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c > index 0343246..a9c33e6 100644 > --- a/drivers/usb/core/hcd-pci.c > +++ b/drivers/usb/core/hcd-pci.c > @@ -188,6 +188,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) > if (pci_enable_device(dev) < 0) > return -ENODEV; > > + retval = dma_coerce_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32)); > + if (retval) > + return retval; dma_coerce_mask_and_coherent is only for platform devices (and I'm not sure it is a good idea to start with, but that is a different story). PCI device should have the dma_mask pointer set already, so you should use dma_set_mask_and_coherent here.