[Linux-parport] IRQ storm from Express card parallel port

Andre Puschmann andre.puschmann at tu-ilmenau.de
Fri Jun 29 14:07:18 EDT 2012

Hi Martin,

On 06/25/2012 02:44 PM, Martin Mokrejs wrote:
> Andre Puschmann wrote:
>> Hi Martin,
>> On 06/25/2012 12:10 PM, Martin Mokrejs wrote:
>>> Hi Andre,
>>>   I played with a card from another vendor based on MosChip. It was stated
>>> in the manual one cannot use IRQ, only memory-mapped IO. When I did use ECP+DMA
>>> my Linux locked up soon. I could print fine but to scan a page I need a lot of luck.
>>> Well, I need a patch which you can find on this list to disable to "fix" which
>>> disabled ECP on many systems, inadverently, and was still necessary for 3.2.5 kernel.
>>> I am attaching them for your convenience.
>>>   I was dreaming about http://www.usbgear.com/USBG-EX-LPT.html which is based
>>> on Oxford chipset, hopefully working in IRQ mode as well.
>> Well, I am not 100% certain but the card came with a driver CD and it
>> contains a inf file for Windows which is copyright by Oxford Technology.
>> So that might mean that my adapter has the Oxford chip. Is there any way
>> to check without breaking the housing?
> Try lspci and also dmesg after loading the proper driver.

Sure, well the chip is indeed an Oxford chip according to lspci.

> I could get the card running in ECP at all. It was only in SPP mode without
> the patch. If your card is running in ECP+DMA mode you don't need them probably.
> Or just try and report back the difference. It is also helpful to know if the patches
> break other systems.

I am afraid I won't find the time to test all modes and the patches,
although I'd wish to. What I am concerned about for now is to get the
interrupt operation work ok. But I'll report back on that as soon as I
find something. In the meanwhile, I am happy to receive any feedback on
this, too.


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