[linux-dvb] Re: Hauppauge Nova-T Problems

[John Knottenbelt <jak97@doc.ic.ac.uk>]

Well, I notice that av7110.c (at least in the 2.6.0-test3 kernel) writes:

./ttpci/av7110.c:       saa7146_write(dev, PCI_BT_V1, 0x1c00101f);

and

./ttpci/budget-core.c:        saa7146_write(dev, PCI_BT_V1, 0x001c0000 |
./ttpci/budget-core.c:            (saa7146_read(dev, PCI_BT_V1) & 
~0x001f0000));

Assuming that budget-core write happens after av7110 then the mask is:

    0x1c00101f
|   0x001c0000
= 0x1c1c101f

Which I believe decodes to:
FIFO Threshold   1: 32 dwords
PCI Burst length 1:  128 dwords
FIFO Threshold   2: 4 dwords
PCI Burst length 2:  16 dwords
FIFO Threshold   3: 4 dwords
PCI Burst length 3:  128 dwords
PCI Burst length DEBI:  128 dwords

So it appears that Budget cards are using 128 dwords for DEBI PCI Burst 
Length.

According to Robert's previous message 128 dwords might be too long for some 
chipsets? 

How can we tell if the chipset can handle these parameters?

Cheers

John

On Saturday 16 August 2003 13:23, Edward Wildgoose wrote:
> > FWIW, these are exactly the symptoms I had on a SIS chipset with a budget
> > card. These cards appear to be very timing sensitive. The parameters to
> > play with are the SAA7146A "FIFO threshold" and "PCI burst length"
> > settings. Settings I found to work well:
> >
> > 1. PCI burst = 32 DWORDs, FIFO threshold = 32 DWORDs - This one handles
> > even a 40Mbps DVB-Cable stream on both i440BX as well as i850E chipsets
> > (don't have others to try).
> >
> > 2. PCI burst = 16 DWORDs, FIFO threshold = 16 DWORDs - seems to work
> > equally well.
> >
> > 3. PCI burst = 16 DWORDs, FIFO threshold = 32 DWORDs - The only setting
> > which allowed me to make a DVB-T budget card work on a SIS 651 chipset.
>
> Well, optimism is ebbing now.  I haven't completely finished trying
> everything, but I don't seem to be making much difference with these
> options.  Can I just check I'm applying them right:
>
> Basically as per:
> http://www.linuxtv.org/mailinglists/linux-dvb/2003/07-2003/msg00171.html
>
> I change av7110.c and change the line:
>
> saa7146_write(saa->mem, PCI_BT_V1, 0x001c0000)
>
> to either 0x00170000 or 0x00130000 for options 1 and 2 (I did also try
> changing all the other registers to something lower as well.)
>
> Then make clean, make, make insmod and off we go.
>
> I have completely disabled all the onboard devices, especially the usb bus,
> and still I have glitches on channel 5 for example.  On many other channels
> I can get the quality to be "pretty good".  However, the sound is WAY out
> of sync, nearly 1 sec or so behind.  This all works fine with the full
> featured card though, and sound is going to an RME audio 96/8 card
>
> I have a few things to try still, but just wanted to check that I'm
> altering the param correctly because I don't really see much change when I
> move it around...
>
> ...Also, one other strange thing.  I have not yet tried adding the debug
> flag, but I do notice that the frontend does not load up properly unless
> the ves1820 module is insmod first.... Any idea why?
>
> Thanks
>
>
> Ed W



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