On Fri, 2008-07-25 at 12:03 -0400, Gerhard R. Wittreich wrote:
> Quoting "Andy Walls" <[EMAIL PROTECTED]>:
> 

> > I'm assuming all the failures above include an I2C bus problems and not
> > just simply an -ENOMEM. At that point I think it's safe to assume it's
> > motherboard PCI chipset (which includes the bridges and memory
> > controller) interaction/errant behavior with respect to the CX23418.
> >
> 
> I did read a few interesting posts regarding linux issue with riser  
> cards.  It appears there may be significant latitude in how mfg's  
> implement pci standards and bridging on riser cards.
> 
> FWIW...Here is a link to an interesting pci riser issue.   
> Unfortunately, this thread also reaches no conclusion/solution.
> 
> http://kerneltrap.org/mailarchive/linux-kernel/2007/2/18/56447


Spec violations or misimplementations aren't uncommon.  Intel's usually
the best about adhering as far as I can tell though.  There errata
sheets show some weird problems though.

I just looked and the 82801 IO controller hub (which is likely
integrated into your 80845 chipset) is a PCI v2.2 compliant set of
devices.

I just read the Product Brief for the CX23418 that is available to the
public from Conexant's website.  The CX23418 is a PCI v2.3 device.

I've now got to go back through all the other reports from users to see
what PCI version their chipsets implement.  I'll post the results with a
query for anyone who has a CX23418 working with a PCI v2.2 or earlier
chipset.

Please verify these findings for yourself (and double check my research)
by pulling the 82845 & 82801 datasheets from Intel and the CX23418
product brief from Conexant.

*** So I think the root cause is a PCI version incompatibility. ***


BTW, the last version of the plain old PCI spec I know of is v3.0.  You
can google for "pci 3.0 spec" and perhaps find sites host the PCI bus
and PCI bridge specs.


> >> What Next?
> >> ----------
> >>
> >> -  Install Win2K on the original box and see if a significant shift in
> >> OS makes a difference.
> >
> > If, when you install Windows, the card doesn't work, then we know that
> > getting the card working in that machine will likely be impossible.
> >
> > If when you install Windows, things work, all that tells us is that
> > Windows doesn't set up the Intel motherboard chipset the same as Linux
> > does, or that it exercises the bus in a manner different than Linux.
> > That means probably quite a few hours of studying the PCI bus specs, the
> > datasheets and errata for the Intel 82845 and 82801 chipsets, the state
> > of the PCI devices registers, and experimentation.  (Datasheets and
> > Errata sheets are available from Intel's website,)

> Ran into a bit of a snag.  The easiest OS for me to install is Win2K.   
> Unfortunately, as I discovered after I finished the build, the  
> Hauppauge software/driver are not available for Win2K...Just XP.  I  
> don't believe it is worth pursuing this route any further.

OK.  For the record, I suspect all that would happen is that you would
verify you have a PCI bus hardware compatibility problem.




> > Out of curiosity, I wonder how many of the c23418's I2C registers are
> > actually affected?
> >
> > Here's the dump of cx18 I2C related registers from my machine:
> >
> >
> > # ./v4l2-dbg -d /dev/video0 -R type=host,chip=0,min=0x2f15000,max=0x2f15023
> > ioctl: VIDIOC_DBG_G_REGISTER
> >
> >                 00       04       08       0C       10       14       
> >  18       1C
> > 02f15000: 00021c0b 00000000 0000000c 00000074 00000807 00000000  
[snip]
> I'll give this a try after I rebuild with Mythbuntu tonight or
> tomorrow.

I just realized you can do this unless you get a '/dev/videoN' node to
show up.  So if you can't, no big deal.


> > You do have the outside chance of a BIOS update and/or adjustment of
> > BIOS settings making things work by configuring the motherboard chipset
> > differently.  For example a BIOS update may configure the motherboard
> > chipset differently to work around Intel's recently published chipset
> > errata (2004 for the 82801).
> >
> 
> I am running the latest Dell BIOS and no updates have been released  
> since 2005.
> 
> The only other thought was using some additional kernel boot  
> parameters.  There are a number of pci boot parameters...Any  
> possibility that one of those might change the pci behavior enough to  
> allow this to work?

I thought of that too, but didn't know what was available off the top of
my head.

> ie...
> 
> PCI
> ---
> pci=off                    Don't use PCI

Not useful.

> pci=conf1            Use conf1 access.
> pci=conf2            Use conf2 access.

I don't think it will be useful, as the most common case is for any
device to implement configuration access method 0, with the others
usually not being implemented


> pci=rom                    Assign ROMs.

Only useful if we thought there was a ROM actually responding to where
the CX23418 had it's addressed mapped.  This one is probably worth a
try.

> pci=assign-busses    Assign busses

Not useful.


> pci=irqmask=MASK     Set PCI interrupt mask to MASK
> pci=lastbus=NUMBER   Scan upto NUMBER busses, no matter what the mptable says.

Not useful.


> pci=noacpi           Don't use ACPI to set up PCI interrupt routing.

May have an effect, but I doubt it would fix any plain old PCI reads and
writes, which are what we have a problem with.


> >
> > After that I'm at a loss.  If it were in front of me along with a PCI
> > bus analyzer (which I also don't have), I'd have a chance of figuring it
> > out after God knows how many hours.  It would be faster/cheaper to get a
> > new motherboard and processor or a different digital video capture card.
> >
> 
> I had reached that same conclusion but was willing to try a few more  
> things in the hopes that this would improve the cx18 driver/contribute  
> to the open source community.  I just ordered a new MB (actually  
> bought a used Dell Optiplex GX280 for $150.)  I'll let you know if  
> that works...I expect it will.

Check the mobo chipset to make sure it's PCI v2.3 or above!




> > You also have the option of leaving the HVR-1600 card in your AMD
> > x2/Fedora 9 system and having that as a Myth backend.  You could use
> > this older computer as only a Myth frontend machine.
> >
> 
> Yes...A possibility.  Once I get the new machine up I will experiment  
> using the new machine as a backend and the old machine as a frontend.


> > You've done an excellent job at troubleshooting and eliminating
> > variable.  Sorry, it doesn't look like it's something that can be solved
> > without hours of study, analysis and experimentation.


> Thanks for all you help.  To bad we didn't solve this one but we gave  
> it a good try.  If you think any of the above PCI boot options is  
> worth trying I will still do that.

Maybe the "rom" one.  I doubt it will fix things.

Regards,
Andy

> --Gerhard



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