Date: Mon, 16 Oct 2006 00:31:25 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: usleepless@gmail.com Cc: freebsd-multimedia@freebsd.org, B Briggs <rcbdyndns@bellsouth.net>, rick-freebsd@kiwi-computer.com Subject: Re: New port: pvrxxx for Hauppauge PVR150/500 Message-ID: <20061016073124.GD23971@funkthat.com> In-Reply-To: <c39ec84c0610152340u2af2aeco611086e50f467a6a@mail.gmail.com> References: <45317970.5000508@bellsouth.net> <20061015064102.8780.qmail@web30310.mail.mud.yahoo.com> <20061016015911.GC57865@keira.kiwi-computer.com> <c39ec84c0610152340u2af2aeco611086e50f467a6a@mail.gmail.com>
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usleepless@gmail.com wrote this message on Mon, Oct 16, 2006 at 08:40 +0200:
> On 10/16/06, Rick C. Petty <rick-freebsd@kiwi-computer.com> wrote:
> >I think it's timing-critical, although an I2C bus has clock and data lines,
> >so I can't see any reason the kernel needs to block during the download.
> >Feel free (anyone) to look into the iic code and pull it out from under
> >GIANT.
>
> will that help? reason i ask is because with the i2c, the cpu is
> responsible for every bit-switch/line-switch in the protocol. so
> through the pci-interface, it tells the card to pull the line up, you
> wait a very short time, and tell it to pull the i2c-line down. etc...
It depends upon the interface... Some things like the bktr have
the ability to drive the i2c bus in hardware.. only if you use the
iicbb (iic bit bang) driver, does the software do all the work...
(though it appears that bktr uses iicbb instead of the hardware)..
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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