On Sat, 09 Apr 2005 16:04:46 +0200 Marcel Holtmann <[EMAIL PROTECTED]> wrote:
> Have you done any work on the binary interface for usbmon so far? I > would be perfect if you can add something like that and then I work on > the usbdump support for it. No, I haven't done anything tangible. I am not a big fan of abstract design, also I do not have a good experience with binary formats or APIs. So, I keep procrastinating with this. I was going to rack your brain for ideas, frankly. Also, there's some work to be done elsewhere (I want to have controls and SCSI commands decoded, for example). The only thing I'll insist on is that the fields had a fixed size, and not "int" or "long". OK, maybe not the only thing, but we'll see. > Since you are using the URB pointer and the kernel timestamp, how do we > deal with the 32-bit userland vs. 64-bit kernel thing? It is not an issue in text formats, as long as the userland does not make assumptions about the word lengths. An application reads them as text words. In ideal world, it makes no assumption about their lengths. In real world, applications allocate buffers for these words, and report errors in case of overflow. So, this is one of advantages of a text format. Once the application starts to convert back to binary, it may hit word size limits and overflows. But if you're willing to declare all fields "long" in Java and "long long" in C, it's all right. If it's vital, I can make timestamps quasi-non-wrapping, to help with ordering of events, for instance. The real issue with tags is fundamentally very annoying and is present in both binary and text formats. In case of Ethernet, all packets are independent, but here we have to establish some identify in order to group events. I still think about some sort of in-kernel tracking. Currently, usbmon is stateless. I had a prototype which tracked URBs, which could conceivably give each transfer a sequential number, but it was fragile and complex. -- Pete ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
