[Openchrome-users] Fwd: K8M890 / DMA

[Thomas Hellström]

Gabriel Mansi wrote:

> Thomas, I sent you the attached e-mail a couple of weeks ago.
> I do not want to bother you, I understand if you are busy. Please let 
> me know if you have received my e-mail.
> I decompiled windows driver for K8M890 and found some interesting 
> intialization functions, I am not sure if any could be for dma.
> If you are interested I will transalate those functions to C and I 
> will send you.


Gabriel,
There is no info from VIA about K8M890 AGP DMA, and therefore I have 
disabled it / will disable it in the DRM until there is a working 
implementation available. I cannot engage in reverse-engineering but 
perhaps there are others on the openchrome list that are willing to.

I'll forward this message to the openChrome list.

Regards,
Thomas




>
> ---------- Forwarded message ----------
> From: *Gabriel Mansi* < gabriel.mansi at gmail.com 
> <mailto:gabriel.mansi at gmail.com>>
> Date: Jan 18, 2007 6:34 PM
> Subject: K8M890 / DMA
> To: thomas at tungstengraphics.com <mailto:thomas at tungstengraphics.com>
>
> Thomas Hellstr?m,
>
> I am trying to determine where is the problem with K8M890 and DMA.
> When I start X with the EnableAGPDMA option X enters in a loop, gdb
> backtrace shows this lines:
>
>         while ((pVia->lastMarkerRead - uMarker) > (1 << 24))
>             pVia->lastMarkerRead = *pVia->markerBuf;
>
>
> I wrote a simple program to get access to video registers:
> http://www.goldinformatica.com.ar/openchrome/registers/v1/registers.c 
> <http://www.goldinformatica.com.ar/openchrome/registers/v1/registers.c>
> It draws a blue rectangle on the screen.
> I am extending it to test DMA but I am not sure how to map DMA memory
> and where is located. I want to do this with a simple program because is
> more easy to track and I can avoid restart X and (un)load drm modules.
>
> Is DMA mapped at agpAddr + agpSize ?
> (II) VIA(0): [drm] agpAddr = 0xf0000000
> (II) VIA(0): [drm] agpSize = 0x01e00000
> (II) VIA(0): [drm] Initialized AGP ring-buffer, size 0x200000 at AGP
> offset 0x1e00000.
>
> Can you help me with that?
>
> Sorry for mi English.
>
> Thanks in advance,
> Gabriel Mansi.
>