Workaround for some broken BIOSes that forgot to enableATAchannels [patch]

[John Baldwin]

On 14-Apr-2003 Soeren Schmidt wrote:
> It seems Maxim Sobolev wrote:
>> > > This is BIOS on my new vprMatrix 175B4 notebook (P4M-1.7GHz).
>> > > Along with ATA, it "forgets" to enable ports on network card
>> > > (fxp driver), I've already committed patch for it. Funny thing
>> > > is that the problem doesn't exists on 4.7 - both ata and fxp
>> > > work here OOB. This might be somehow related to ACPI, but
>> > > forcefully disabling it in 5-CURRENT doesn't help.
>> > 
>> > I heard BIOSes, and now its just one :)
>> > 
>> > I'll wait and see if there is more of this, before committing code that
>> > might be just a one off...
>> 
>> :(((
>> 
>> I am really wonder why ata driver is so strict in this area.
>> Many other drivers don't rely on BIOS to do the right job and
>> enable ports, memory space and busmastering explicitly. And
>> this is the right thing (IMO), since most modern operating
>> systems including FreeBSD don't give a shit to BIOS settings
>> anyway. If device is probed and user didn't disable the driver
>> explicitly, it should do everything to attach to device, no
>> matter in which weird state the BIOS left it.
> 
> The current way of things are implemented because:
> 1. Users wanted our driver to honor the BIOS setting an ATA channel on or off

This isn't always easy, esp. when we start supporting PNP OS = yes at
some point.

> 2. If the BIOS doesn't enable the port, it most likely hasn't setup 
>    interrupt routing etc as well..

When I get PCI interrupt routing working right on SMP I plan to always
reroute PCI interrupts.  In the case of UP and an unrouted interrupt,
we already route the interrupt properly anyways.

A note to Maxim: please use pci_enable_io() instead of messing with
the config regs directly.

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/