--- On Thu, 5/13/10, Rob Duncan <Robert.Duncan@xxxxxxxx> wrote: > From: Rob Duncan <Robert.Duncan@xxxxxxxx> > Subject: Re: g_serial and cdc_acm communications > To: "Ron Madrid" <ron_madrid@xxxxxxxxxxxxx> > Cc: "Oliver Neukum" <oliver@xxxxxxxxxx>, "linux-usb@xxxxxxxxxxxxxxx" <linux-usb@xxxxxxxxxxxxxxx> > Date: Thursday, May 13, 2010, 11:49 AM > > On May 13, 2010, at 10:11 AM, Ron Madrid wrote: > > > This is the last (failing) transfer that occurs. > The third > > line is my app receiving information about the data it > should > > expect, and the size of the transfer in dwords, 0x7d0 > (8000 > > bytes). I then see, in subsequent lines, 7 * > 1024 bytes > > received (Bi) followed by 832 bytes received which > totals up > > to 8000 bytes. > > I suspect it's because that host controller is waiting for > the end of > the transfer. 832 bytes is an exact multiple of > 64-bytes, which means > that the the HC is waiting for a short packet, or up to > your transfer > size, which appears to be 1024. I'm read()ing 8000 bytes. I just tried read()ing 8004 bytes and I saw a similar failure. Also, this 8000/8004 byte read() is in a 10000 iteration loop and is successful a seemingly arbitrary number of times (a few dozen to a few hundred) before failing. I had read about a zpl problem before, but this doesn't seem to be the case unless I'm missing something. Ron -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
