From 437052516779fea608261a50682b124315f48f01 Mon Sep 17 00:00:00 2001 From: "inaky@linux.intel.com" Date: Wed, 11 Oct 2006 20:05:58 -0700 Subject: usb/hub: allow hubs up to 31 children Current Wireless USB host hardware (Intel i1480 for example) allows up to 22 devices to connect, thus bringing up the max number of children in the WUSB Host Controller to 22 'fake' ports. Upcoming hardware might raise that limit. Makes almost no difference to go to 31, as the bit arrays are byte-aligned (plus an extra bit in general), so 22 bits fit in 4 bytes as 31 do. As well, the only other array that depends on USB_MAXCHILDREN is 'struct usb_hub->indicator'. By declaring it 'u8' instead of 'enum hub_led_mode', we reduce the size of each entry from 4 bytes (in i386) to 1, which will add as we when are doubling USB_MAXCHILDREN (with 16 the size of that array is 64 bytes, with 31 would be 128; by using u8 that goes down to 31 bytes). Signed-off-by: Inaky Perez-Gonzalez Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/usb.h') diff --git a/include/linux/usb.h b/include/linux/usb.h index 5482bfb3303d..e5cb1690975a 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -313,8 +313,13 @@ struct usb_bus { /* This is arbitrary. * From USB 2.0 spec Table 11-13, offset 7, a hub can * have up to 255 ports. The most yet reported is 10. + * + * Current Wireless USB host hardware (Intel i1480 for example) allows + * up to 22 devices to connect. Upcoming hardware might raise that + * limit. Because the arrays need to add a bit for hub status data, we + * do 31, so plus one evens out to four bytes. */ -#define USB_MAXCHILDREN (16) +#define USB_MAXCHILDREN (31) struct usb_tt; -- cgit v1.2.3