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Date:      Thu, 15 May 1997 13:46:53 -0700
From:      Amancio Hasty <hasty@rah.star-gate.com>
To:        Brad Parker <brad@parker.boston.ma.us>
Cc:        multimedia@FreeBSD.ORG
Subject:   Re: questions about current bt848 code 
Message-ID:  <199705152046.NAA11424@rah.star-gate.com>
In-Reply-To: Your message of "Thu, 15 May 1997 16:25:50 EDT." <199705152025.UAA02908@compaq.parker.boston.ma.us> 

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Whats up Mr Linux 8)

Just talk to the XFree86 people about the snow it sounds like 
you have a DRAM card and also ask them about their Linux DGA extension.
the snow can be caused by incorrect programming of the S3 chipset.
Grab mtv , play an mpeg movie and chances are that you will see the
same effect .


Also, in bktr_intr you can uncomment the line which prints the status
registers with that you ought to figure out why is the Bt848 stopping.
If you can't interpret the status register just send me the output of the
last 100 or so lines.

Whats your system configuration:
CPU
Motherboard
PCI chipset
video card

Last but not least play around with your BIOS settings . Better yet
post your current BIOS PCI settings.

	Cheers,
	Amancio


>From The Desk Of Brad Parker :
> 
> You've been so kind listening to my questions, I hesistate to ask more
> but (what the heck!)
> 
> - I have a "working" port of the freebsd snapshot bt848 driver for linux.
> The signal and mmap interface work fine, as well as the read interface
> if I comment out the code to wait for a frame (and assume that the capture
> ioctl has been called, as the meteor examples/single.c program does).
> 
> - Naturally I have an S3 card.  I have XFree 3.2 also.  I can't get
> "direct" mode to work right.
> 
> If I use "fxtv -disableDirectV" I get live video (since that uses the
> mmap interface) which looks ok, but has a little "snow" all over the
> screen at regular intervals...  (reminds me of when we used to write
> into the frame buffer during on-screen time and the non-dual ported
> ram would have to arbitrate between the bus and the video and the
> video would loose).
> 
> If I use "fxtv" I get a blank screen - but when I hit the middle mouse
> button in the title bar part of the screen fills in (dont' ask me why).
> I did some experiments mapping the frame buffer into kernel space and
> using memset, etc... I the address being given to the dma engine is
> right... it looks like the dma is stopping at random places.  (I assume
> the pci bus master operating in the "physical address space", i.e. no
> mmu mapping is going on out there).
> 
> Any ideas?  I'm wondering if the X server has the addresses space cached and
> I need to disable the caching...
> 
> -brad





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