On 2012/9/5 22:39, Alan Stern wrote:
On Wed, 5 Sep 2012, Lan Tianyu wrote:
This is copied from xhci_usb3_hub_descriptor().
struct usb_hub_descriptor {
__u8 bDescLength;
__u8 bDescriptorType;
__u8 bNbrPorts;
__le16 wHubCharacteristics;
__u8 bPwrOn2PwrGood;
__u8 bHubContrCurrent;
/* 2.0 and 3.0 hubs differ here */
union {
struct {
/* add 1 bit for hub status change; round to bytes */
__u8 DeviceRemovable[(USB_MAXCHILDREN + 1 + 7) / 8];
__u8 PortPwrCtrlMask[(USB_MAXCHILDREN + 1 + 7) / 8];
} __attribute__ ((packed)) hs;
struct {
__u8 bHubHdrDecLat;
__u16 wHubDelay;
__u16 DeviceRemovable;
} __attribute__ ((packed)) ss;
} u;
} __attribute__ ((packed));
The struct has been defined with __attribute__ ((packed)). So there is
no alignment problem. Or we can
hub->descriptor->u.ss.DeviceRemovable = (__force __u16)
cpu_to_le16(port_removable);
I think we also should define wHubDelay and DeviceRemovable as __le16
for ss since they are little-endian order, right?
Yes. Ask Sarah about changing it.
hi Sarah:
Do you have some comments about this?
Alan Stern
--
Best Regards
Tianyu Lan
linux kernel enabling team
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
