diff options
Diffstat (limited to 'include/linux/usb.h')
| -rw-r--r-- | include/linux/usb.h | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/include/linux/usb.h b/include/linux/usb.h index 19fabc487beb..a34fa89f1474 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -195,7 +195,7 @@ struct usb_interface { struct device dev; /* interface specific device info */ struct device *usb_dev; - int pm_usage_cnt; /* usage counter for autosuspend */ + atomic_t pm_usage_cnt; /* usage counter for autosuspend */ struct work_struct reset_ws; /* for resets in atomic context */ }; #define to_usb_interface(d) container_of(d, struct usb_interface, dev) @@ -551,13 +551,13 @@ extern void usb_autopm_put_interface_async(struct usb_interface *intf); static inline void usb_autopm_enable(struct usb_interface *intf) { - intf->pm_usage_cnt = 0; + atomic_set(&intf->pm_usage_cnt, 0); usb_autopm_set_interface(intf); } static inline void usb_autopm_disable(struct usb_interface *intf) { - intf->pm_usage_cnt = 1; + atomic_set(&intf->pm_usage_cnt, 1); usb_autopm_set_interface(intf); } @@ -1036,9 +1036,10 @@ typedef void (*usb_complete_t)(struct urb *); * @transfer_flags: A variety of flags may be used to affect how URB * submission, unlinking, or operation are handled. Different * kinds of URB can use different flags. - * @transfer_buffer: This identifies the buffer to (or from) which - * the I/O request will be performed (unless URB_NO_TRANSFER_DMA_MAP - * is set). This buffer must be suitable for DMA; allocate it with + * @transfer_buffer: This identifies the buffer to (or from) which the I/O + * request will be performed unless URB_NO_TRANSFER_DMA_MAP is set + * (however, do not leave garbage in transfer_buffer even then). + * This buffer must be suitable for DMA; allocate it with * kmalloc() or equivalent. For transfers to "in" endpoints, contents * of this buffer will be modified. This buffer is used for the data * stage of control transfers. @@ -1104,9 +1105,15 @@ typedef void (*usb_complete_t)(struct urb *); * allocate a DMA buffer with usb_buffer_alloc() or call usb_buffer_map(). * When these transfer flags are provided, host controller drivers will * attempt to use the dma addresses found in the transfer_dma and/or - * setup_dma fields rather than determining a dma address themselves. (Note - * that transfer_buffer and setup_packet must still be set because not all - * host controllers use DMA, nor do virtual root hubs). + * setup_dma fields rather than determining a dma address themselves. + * + * Note that transfer_buffer must still be set if the controller + * does not support DMA (as indicated by bus.uses_dma) and when talking + * to root hub. If you have to trasfer between highmem zone and the device + * on such controller, create a bounce buffer or bail out with an error. + * If transfer_buffer cannot be set (is in highmem) and the controller is DMA + * capable, assign NULL to it, so that usbmon knows not to use the value. + * The setup_packet must always be set, so it cannot be located in highmem. * * Initialization: * |