Jiri Kosina wrote: > I agree. I am aware of devices for which just inspecting the parsed data > would be OK (some keyboards with usage mappings which are not defined by > HUT, for example), but also of devices which require special handling on > the report level - Robert Marquardt pointed me in a private mail to a few > devices which are broken par-excellence, and for which handling on report > level would be convenient. > > Also, handling on report level would be nice to have so that we could hook > a hidraw driver to it.
Just forgot to use "Reply All". Here is the text (expanded): Definitely. I know of several devices where the HID descriptor and the data sent completely disagree. A Metex USB Multimeter for example tells that it has a 4 byte report divided into a 3 byte and a 1 byte element. The device sends two reports each containing two 2 byte elements with one in the second report not containing data. The wierdest device is a CD archive torus which shows up as a simple standard mouse. Commands are sent by *reading* strings. The Office Rocket Launcher is posing as a keyboard and reacts to the LEDs being set (this is of interest for the Num-Lock thread here). I definitely hope that the latter two devices will never get official kernel support in any way. Why is the report parsed on driver level at all? It should be possible to allow drivers to manipulate the reports, but i see no reason to split the report into usages that early. The Windows HID API parses the report happily in the HID.DLL for user programs. Drivers have the same API available on kernel level. So a raw API for the drivers should be the primary API. It is usually easier to manipulate the report directly instead of abstract operations. It is also fairly safe. The device has been identified so the offending report layout can be presumed. Parsing for specific usages should be done from the driver. Preparsing the report before the data is handed to the driver only wastes CPU cycles. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
