Greg KH wrote:
On Wed, Feb 13, 2008 at 03:54:38PM +0000, Sergio Callegari wrote:
Hi,
I have an ONDA N501HS (namely a rebranded ZTE MF330) UMTS pc card.
I am currently using this card with the sierra driver (as in current kernels).
Which kernel version specifically?
Ubuntu's 32bit i386 2.6.22
However I am noticing the following problem:
- when I use the card for downloading from the internet, everything is fine;
- when I use the card for uploading to the internet, after a few tens kB, the
card freezes.
Freezing goes as follows:
the card provides 3 ports: ttyUSB0 to ttyUSB2. The port ttyUSB0 that is used for
data stops working completely. It becomes impossible to talk to it, until the
pc-card is extracted and put again in the pcmcia slot. The other ports keep
working.
I wonder if this might have something to do with flow control (or lack thereof)
that causes the card to be flooded with data from the computer until it locks.
Probably.
I believe that flow control might be the issue, since if I use upload programs
that let me decide the data rate and I pick a low enough rate everything goes
just fine.
I have also seen that the ZTE MF330 has just been moved from the sierra driver
to the option driver.
Is there any chance that this might fix my problem?
Well, it might, as it turns out that this really is not a sierra
wireless based device, it's something else.
So try changing drivers and see if that gets better.
Ok. Il'll give the option driver a try and provide some feedback.
The option driver has the words
This driver exists because the "normal" serial driver doesn't work too well
with GSM modems. Issues:
- data loss -- one single Receive URB is not nearly enough
- nonstandard flow (Option devices) control
- controlling the baud rate doesn't make sense
at the beginning... I hope that the thing about flow control applies and
is not an "Option" specific thing.
In any case, I know that ZTE MF330 is not a sierra, but if I am not
wrong it should have the same qualcomm chipset as sierra devices, with
different firmware.
Hence I wonder if someone else might have experienced similar issues as
mine on other cards.
If this is the case, having my distribution kernel source, once I have applied
the patch, how can I rebuild _only_ the sierra and the option modules?
make M=drivers/usb/serial/
will build only that one directory.
Or:
make drivers/usb/serial/option.ko
should build only that module.
You might have to do a 'make oldconfig' and 'make prepare' first though.
Hope this helps,
greg k-h
Thanks!
Sergio
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