Re: PCTV 290e page allocation failure

[Gianluca Gennari <gennarone@gmail.com>]

Il 02/02/2012 20:07, Devin Heitmueller ha scritto:
> On Thu, Feb 2, 2012 at 2:02 PM, Gianluca Gennari <gennarone@gmail.com> wrote:
>> I'm trying to reproduce the problem with another em28xx-dvb device to
>> see if it is not restricted to the PCTV 290e. Before the PCTV 290e, I
>> was using a different device with a driver based on the dvb-usb
>> framework, and I never observed similar crashes.
> 
> On ARM based platforms it is very likely you will run into this issue
> with most USB based tuners.  It's because over time there is memory
> fragmentation that occurs which prevents being able to allocate large
> enough chunks of coherent memory.
> 
> Making such a scenario work would require hacks to the driver code to
> preallocate the memory in some form of static pool at system boot (or
> perhaps at driver initialization), and then reuse that memory instead
> of attempting to allocate it as needed.
> 
> Devin
> 

Hi Devin,
thanks for the explanation. The CPU is MIPS based (not ARM) but I guess
there is not much of a difference from this point of view.
As I mentioned in my first reply, I never had this kind of errors when I
was using a dvb-usb USB stick. Now I'm trying to replicate the problem
with a Terratec Hybrid XS (em28xx-dvb + zl10353 + xc2028), and so far
I've stressed it for a few hours without problems. We will see in a day
or two if I can make it fail in the same way.

Regards,
Gianluca