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authorMark Brown <broonie@linaro.org>2013-08-27 15:40:03 +0100
committerMark Brown <broonie@linaro.org>2013-08-27 15:40:03 +0100
commitdc1632321ba1e93dde25870e96cebe21b7d52517 (patch)
treed52d934c79b23f91654c571d983e1a6ec41b71fd /include/uapi/linux/usb
parent8c193b8dce4f2a2474dc2bc39ec972454df9d439 (diff)
parenta85f9da707366e856c0aad9e329db0cc59475290 (diff)
Merge remote-tracking branch 'asoc/topic/dmic' into asoc-core
Diffstat (limited to 'include/uapi/linux/usb')
-rw-r--r--include/uapi/linux/usb/ch11.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/uapi/linux/usb/ch11.h b/include/uapi/linux/usb/ch11.h
index 7692dc69ccf7..331499d597fa 100644
--- a/include/uapi/linux/usb/ch11.h
+++ b/include/uapi/linux/usb/ch11.h
@@ -11,6 +11,17 @@
#include <linux/types.h> /* __u8 etc */
+/* 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
+ * use 31, so plus one evens out to four bytes.
+ */
+#define USB_MAXCHILDREN 31
+
/*
* Hub request types
*/