Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Andy Furniss <andyqos@ukfsn.org>]

Gianluca Gennari wrote:
> (was: Re: PCTV 290e page allocation failure)
>
> On MIPS/ARM set-top-boxes, as well as old x86 PCs, memory allocation failures
> in the em28xx driver are common, due to memory fragmentation over time, that
> makes impossible to allocate large chunks of coherent memory.
> A typical system with 256/512 MB of RAM fails after just 1 day of uptime (see
> the old thread for detailed reports and crashlogs).
>
> In fact, the em28xx driver allocates memory for USB isoc transfers at runtime,
> as opposite to the dvb-usb drivers that allocates the USB buffers when the
> device is initialized, and frees them when the device is disconnected.
>
> Moreover, in digital mode the USB isoc transfer buffers are freed, allocated
> and cleared every time the user selects a new channel, wasting time and
> resources.

Does this patch have a chance of getting in?

I am still having to flush caches before use. If you want more testing I 
can give it a go. I didn't earlier as I didn't have a git to apply it to 
and thought it was going to get in anyway.