I have to agree with JE, there should be a common API for drivers to reserve bandwidth on a per-ep basis, and then any URBs submitted are guaranteed not to fail from a shortage of bandwidth.
However, I don't think BW can be calculated effectively by common code, it is dependent on the HCD. On Sat, 12 Oct 2002, David Brownell wrote: > >>>>>So it's a Good Thing that Linux allocates bandwidth only on demand ... :) >>>> >>>>You mean at open() time right? :) >>> >>>That's the driver's business. If they post URBs on open, that >>>would be how it works. If they post URBs on read/write, it'd be >>>a bit different. >> >> >> It needs to be as early as possible to inform the application. >> >> Once they start reading or writing successfully. They cannot be denied >> the bandwidth they have already reserved later. > >Those are two very different policies. I certainly agree with the >second one; that's the point of reserving. > >Not the first ... that's a policy agreed on by the app and its driver. >If they want to be able to open devices "early" (say, to address >permissions problems by handing off file descriptors as opposed to >changing device permissions) and allocate bandwidth later (by issuing >some kind of read) that's their business. > >- Dave > > > -- Dan Streetman [EMAIL PROTECTED] --------------------- 186,272 miles per second: It isn't just a good idea, it's the law! ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
