Return-Path: Message-ID: <40E12F15.9040805@thomae-privat.de> Date: Tue, 29 Jun 2004 10:57:57 +0200 From: Matthias Thomae MIME-Version: 1.0 To: Marcel Holtmann Cc: BlueZ Mailing List Subject: Re: [Bluez-users] Epox Barton keyboard: HID create error 53 References: <40CDE18C.70703@thomae-privat.de> <1087255678.13792.51.camel@pegasus> <40CE96A8.3020407@thomae-privat.de> <1087284859.13792.67.camel@pegasus> <40CEC020.6050107@thomae-privat.de> <1087292887.13792.81.camel@pegasus> <40CF4B17.2010806@thomae-privat.de> <1087339715.13792.104.camel@pegasus> <40D7DDAD.2040908@thomae-privat.de> <1087897207.4328.89.camel@pegasus> <40D8D39E.3070301@thomae-privat.de> <40E024AD.1000101@thomae-privat.de> <1088452526.6030.86.camel@pegasus> In-Reply-To: <1088452526.6030.86.camel@pegasus> Content-Type: text/plain; charset=us-ascii; format=flowed List-ID: Hi Marcel, the HID Specification 1.11 states on page 19: "Multibyte numeric values in reports are represented in little-endian format, with the least significant byte at the lowest address." So it really is 65280, isn't it? Also, I got this value by use of the HID Descriptor Tool. Moreover, the descriptor of the Apple keyboard, according to your web page, has a similar sequence the other way round: "2a ff 00" The funny thing is, the Windows Widcomm Bluetooth stack seems to cope with this, I tried it on a Thinkpad. So what do we do? Greetings Matthias Marcel Holtmann wrote: >>is caused by the item USAGE_MAXIMUM(65280) which corresponds to "2A 00 >>FF", the 18th item of the descriptor (see below). The maximum number of >>usages is set in net/bluetooth/hidp/hid.h >> >>#define HID_MAX_USAGES 1024 >> >>I tried to increase this to 65535 (FFFF), the theoretical max according >>to HUT 1.11, but it didn't help, because then the max page size is exceeded. >> >>But this doesn't seem reasonable anyway, since the codes E8-FFFF are not >>defined yet (and which keyboard has several tens of thousand keys? ;). >> >>So, can we assume the HID descriptor is "broken"? If yes, what would be >>the way to deal with this? Can we re-set the USAGE_MAXIMUM to a >>reasonable value? > > > I don't know if the descriptor is broken or if the HID parser has a bug. > > The value you are talking about is 255 and not 65280. The questions is > if the descriptor encodes these values in big or in little endian. If > they must be in little endian than EPoX made a mistake here, otherwise > our HID parser is broken. Please check the specification for the used > endian encoding, because I will not have time to read it. > > Regards > > Marcel > >