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List:       freebsd-hackers
Subject:    Re: Kernel config - passing flags to a PCI device
From:       Mike Smith <mike () smith ! net ! au>
Date:       1998-10-29 23:59:26
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> Roger wrote
> > > Is it possible to pass flags from a kernel config to a PCI device
> > > I would like them in the bt848/878 driver.
> > > eg, device bktr0 flags 0x0103
> > >
> 
> Mike wrote
> > No.  You should be detecting this automatically
> > anyway; that's what PCI is for.
> 
> I agree you can read a manufacturer and model number from PCI chips.
> Very usefull too.
> In my case, I need the flags for things you cannot discover from the
> PCI chipset.

I'm curious; how does the vendor-supplied software know whether it's 
talking to the right sort of card?  Does it just make assumptions?

> CASE 2: On the Bt848 based frame grabbers, all you can get back from
> the PCI probe is "Manufacturer - Brooktree" and "model - BT848" Each of
> the different TV cards based on the bt848 use different tuner types.
> There is no way to probe the card to determine the tuner type or the OEM
> of the TV card. Currently, there are more kernel options and even some
> sysctls to specify this to the kernel driver. I would like this to be in
> a flags setting for each card.

Use an ioctl to configure the driver on a per-device basis.  Have a 
control app that reads a configuration file using a user-supplied model 
name as an index.  Don't get sidetracked by a stupid anti-ioctl 
flameware again.

Alternatively, use a sysctl node and instantiate multiple settings 
groups yourself.  This sucks more than it should because of the way 
that sysctl works at the moment.

> So, back to the question. How can I pass flags to a PCI device?

You don't.  You never will.

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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