Skip to main content

Browse the archive

Revision bc2e4a90d9f75f1664c1587eb09ecd10bb71b022 authored by Linus Torvalds on 03 March 2013, 18:24:57 UTC, committed by Linus Torvalds on 03 March 2013, 18:24:57 UTC 
Merge tag 'usb-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
 
Pull USB patch revert from Greg Kroah-Hartman:
 "Here is one remaining USB patch for 3.9-rc1, it reverts a 3.8 patch
  that has caused a lot of regressions for some VIA EHCI controllers."

* tag 'usb-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: EHCI: revert "remove ASS/PSS polling timeout"
2 parent s 68b86a2 + 221f8df
Raw File
ioctl-decoding.txt 
To decode a hex IOCTL code:

Most architectures use this generic format, but check
include/ARCH/ioctl.h for specifics, e.g. powerpc
uses 3 bits to encode read/write and 13 bits for size.

 bits    meaning
 31-30	00 - no parameters: uses _IO macro
	10 - read: _IOR
	01 - write: _IOW
	11 - read/write: _IOWR

 29-16	size of arguments

 15-8	ascii character supposedly
	unique to each driver

 7-0	function #


So for example 0x82187201 is a read with arg length of 0x218,
character 'r' function 1. Grepping the source reveals this is:

#define VFAT_IOCTL_READDIR_BOTH         _IOR('r', 1, struct dirent [2])
back to top