[ale] [Slightly OT] Prolific

[mike at trausch.us]

On 11/04/2012 07:12 PM, Sam Rakowski wrote:
> I've a PL2303 based serial cable that has worked fine for me, on the
> off chances when I get to use it.

Interesting.

I must be sorely unlucky.  :)

This one that I bought from fry's the other day doesn't work with Linux, 
doesn't work with Windows, and spams the kernel ring buffer with all 
sorts of error messages.

If it were the first prolific device I ever bought, I'd assume it was 
defective.

I bought a parallel cable ages ago (actually, I bought like six of them, 
from various places, because I was stupidly frustrated).  I even went 
with different brands, only to find out that they were all built around 
the same stupid Prolific chipset.  The problem with them all was the 
same:   Whenever I would send a print job to the printer, the printer 
would seemingly do nothing.  I could then try to cat things to the 
printer, which would simply hang.  By some strange turn of events, I 
realized that if I pressed the printers ON LINE button twice, to bring 
it offline and then back online, the printer would start printing the 
stuff I sent to it, but the first byte would be missing from the stream.

Given the popularity of some of the brands (Belkin, for example, was one 
of them), I thought that it must surely be a bug in the Linux kernel. 
So, I tried in Windows.  Same problem.  Printer?  No, it worked with a 
real parallel port, and a parallel-port inkjet wouldn't print at all (no 
way to toggle the ONLINE pin).

Greg KH, a kernel dev, has apparently been getting bad reports about 
Prolific hardware for a long time.  Anymore it seems that if someone 
comes to linux-usb to whine about it not working, he says "go get a real 
piece of hardware from FTDI".

I wonder why they're such a problem.

I wonder why yours actually works.

And yes, I tested this cable with a Windows laptop.

RING

RING

comes in, but nothing ever gets out... bits can check in any time they 
like, but they can never leave...

	--- Mike

-- 
A man who reasons deliberately, manages it better after studying Logic
than he could before, if he is sincere about it and has common sense.
                                    --- Carveth Read, “Logic”