Re: 2.4.30 - USB serial problem

From: Ian Leonard
Date: Thu Jun 02 2005 - 03:59:47 EST


Pete Zaitcev wrote:
On Thu, 26 May 2005 18:52:10 +0100, Ian Leonard <ian@xxxxxxxxxxxxx> wrote:


We recently upgraded from 2.4.24 to 2.4.28 and the problem described below appeared. I have tested it on 2.4.30 and the fault still exists.
[...]
Examining the packet that caused the problem showed it was very similar to the others but it contained 0x0a. This obviously stuck out as being a candidate for some sort of translation problem.


The above looks almost too obvious but for this:


I also built a 2.4.28 kernel with the ftdi_sio and usbserial code from the 2.4.24 release. It also failed. This was a surprise and I am wondering of I did it correctly.


Did you nail down a scenario which we can debug? Frankly it's not credible

Not as yet. As I indicated I can only test the problem at a remote site and I don't get much time to look at it.

that transplanted usbserial and ftsi_sio would fail to work. I know that

I agree, it can't be the case. To prove that I hadn't just made a mistake, I transplanted the whole usb branch and it still failed. This really points to the user app - which is complex and I haven't got to the bottom of it. It's a multi-threaded library and I see it's doing some sort of packet requeuing based on a timer. I can't see what has changed but I am guessing it's a kernel timing issue. It would explain everything.

I changed quite a bit between 2.4.24 and 2.4.28, but your experiment
undoes that.

I think the usb is red herring - sorry about that. BTW, I see you have cc'd Ian (hi Ian). By coincidence we are using an MEV usb device.


--
Ian Leonard

Please ignore spelling and punctuation - I did.
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