On 25/02/2008, Greg KH <[EMAIL PROTECTED]> wrote: > On Mon, Feb 25, 2008 at 09:18:12AM -0800, Chetan Karia wrote: > > On 22/02/2008, Greg KH <[EMAIL PROTECTED]> wrote: > > > On Fri, Feb 22, 2008 at 05:30:22PM -0800, Chetan Karia wrote: > > > > On 22/02/2008, Greg KH <[EMAIL PROTECTED]> wrote: > > > > > On Wed, Feb 20, 2008 at 10:35:48AM -0800, Chetan Karia wrote: > > > > > > Hello, > > > > > > > > > > > > I am kernel newbie and I have a question about usb serial > driver. I > > > > > > have a usb to serial driver which exposes 3 virtual serial ports > > > > > > ttyUSB0, ttyUSB1 and ttyUSB2. The endpoint to virtual serial port > > > > > > mapping is like this > > > > > > ep0 ==> ttyUSB0 > > > > > > ep1 ==> ttyUSB1 > > > > > > ep2 ==> ttyUSB2. > > > > > > > > > > > > > > > Which device is this? I think you are talking about the endpoint > > > > > "pairs" one IN and one OUT per tty, right? > > > > > > > > > Yes I am talking about endpoint per one IN and one OUT per tty. > > > > > > > > > But what physical device is this? > > > > > This is the sierra wireless device. > > > Usually you use PPP over this kind of connection, by providing two > read/write ports to it, you have the very large chance of messing up the > ppp protocol, correct? > > What specifically are you trying to do in userspace that you need two > reads or writes to do that is not working today?
Alright, here is the entire situation. The sierra device has pair of endpoints (bulk in and bulk out) that sends the multiplexed protocols data packets ( two protocols data packets encapsulated in one). Lets call that endpoint pair as EP1. The one of the multiplexed protocol is DM and other is command and status. EP1 is attached to ttyUSB1. Our application reads from ttyUSB1 and ignores DM packets and considers only command and status packets. However to get DM stream working another application has to read/write to ttyUSB1 concurrently which is as tricky. Thus, I am trying to setup another virtual serial port called ttyUSB3 that can read/write to EP1 concurrently so that we get two duplicate streams. One of the stream (ttyUSB1) can be used by our existing application and another stream (ttyUSB3) can be used to set up DM logging.Internally however they will talk to same endpoint pair EP1. Is it doable? Hopefully I was able to explain the situation clearly. Thanks, Chetan Karia > > > > We can write to a single port concurrently from 2 programs but can two > > programs READ the same stream simultaneously? > > > They can try, but things get very confusing very quickly :) > > thanks, > > greg k-h > - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
