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
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