[LAU] Graphic card

[Len Ovens]

On Sun, 28 Dec 2014, Gene Heskett wrote:

> On Sunday 28 December 2014 09:24:29 Raphaël Mouneyres did opine
> And Gene did reply:
>> Le 26 déc. 2014 à 09:26, David Christensen <dpchrist at holgerdanske.com> a 
> écrit :
>> > 1.  Some chips (Atom?) have proprietary graphics without Linux
>> > support.
>> 
>> I have two Intel D525MW Atom based boards running Archlinux, video
>> driver is working perfectly out of the box. I use those board to do
>> realtime audio using linux sampler and RME PCI audiocard, it does an
>> excellent job.
>
> I can duplicate that story with 2 of them, running the 10.04.4 LTS Ubuntu 
> linux server edition, with a special rtai patched realtime kernel, running 
> a lathe and a milling machine.  Some folks would call that dangerous 
> machinery. But the on board i915 video works flawlessly, and quite a bit 
> faster than VESA.  These are machines that would get retired or the job 
> offloaded to a $90 specialty card if the IRQ latency ever went above 5 
> microseconds.  More usual measurement is 2 microseconds. For this bit of 
> critical usage, all one can say about them is that they Just Work(TM).

Certainly the video "works" OOTB with these boards. there is nothing that 
just doesn't display or anything like that. It is just that linux (and 
newer windows) doesn't use the full ability of the GPU. This, in some 
applications, makes the whole board look slower than it acually is because 
the CPU has to take over the GPU's job for some things. There are many 
applications where the graphics are not that critical such as running 
Ardour and friends that do not show any problem with the video at all. On 
mine the memory is limited to 4G and the netbook is 2G which might in some 
cases be a problem (I find 1G too small and 2G ok). The word "desktop" to 
me means running more than just audio apps and the GPU/drivers seem to 
fail in that context (that is use too much CPU for smooth, up to speed video).

There was one or two kernels that did have a full driver (from Intel) and 
10.04 may have been when (sounds about right to me). So using a 
distro/kernel of that age may work better. My comments are based on 14.04.

However, I will agree that these are a very good low latency/RT machine. 
Even running Kubuntu with the lowlatency kernel allows me no xruns as low 
as the audio IF will work. The video might be slow, but the audio just 
works.

--
Len Ovens
www.ovenwerks.net