diff options
Diffstat (limited to 'drivers/usb/core/usb.c')
| -rw-r--r-- | drivers/usb/core/usb.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 5e80697ef952..592151461017 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -440,7 +440,18 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent, dev->dev.bus = &usb_bus_type; dev->dev.type = &usb_device_type; dev->dev.groups = usb_device_groups; + /* + * Fake a dma_mask/offset for the USB device: + * We cannot really use the dma-mapping API (dma_alloc_* and + * dma_map_*) for USB devices but instead need to use + * usb_alloc_coherent and pass data in 'urb's, but some subsystems + * manually look into the mask/offset pair to determine whether + * they need bounce buffers. + * Note: calling dma_set_mask() on a USB device would set the + * mask for the entire HCD, so don't do that. + */ dev->dev.dma_mask = bus->controller->dma_mask; + dev->dev.dma_pfn_offset = bus->controller->dma_pfn_offset; set_dev_node(&dev->dev, dev_to_node(bus->controller)); dev->state = USB_STATE_ATTACHED; dev->lpm_disable_count = 1; |