• Jiri Kosina's avatar
    HID: use debugfs for report dumping descriptor · a635f9dd
    Jiri Kosina authored
    It is a little bit inconvenient for people who have some non-standard
    HID hardware (usually violating the HID specification) to have to
    recompile kernel with CONFIG_HID_DEBUG to be able to see kernel's perspective
    of the HID report descriptor and observe the parsed events. Plus the messages
    are then mixed up inconveniently with the rest of the dmesg stuff.
    
    This patch implements /sys/kernel/debug/hid/<device>/rdesc file, which
    represents the kernel's view of report descriptor (both the raw report
    descriptor data and parsed contents).
    
    With all the device-specific debug data being available through debugfs, there
    is no need for keeping CONFIG_HID_DEBUG, as the 'debug' parameter to the
    hid module will now only output only driver-specific debugging options, which has
    absolutely minimal memory footprint, just a few error messages and one global
    flag (hid_debug).
    
    We use the current set of output formatting functions. The ones that need to be
    used both for one-shot rdesc seq_file and also for continuous flow of data
    (individual reports, as being sent by the device) distinguish according to the
    passed seq_file parameter, and if it is NULL, it still output to kernel ringbuffer,
    otherwise the corresponding seq_file is used for output.
    
    The format of the output is preserved.
    Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
    a635f9dd
hid-core.c 57.4 KB