Re: [PATCH] 2.5.5-pre1 IDE cleanup 9

Martin Dalecki
2002-02-23T14:54:20Z

Jeff Garzik wrote:
> Andre Hedrick wrote:
>
>>On Fri, 22 Feb 2002, Jeff Garzik wrote:
>>
>>
>>>Andre Hedrick wrote:
>>>
>>>>Also not that ATA/IDE drivers were not using 2.4 PCI API and likewise was
>>>>stable for a while.
>>>>
>>>Stable? Yes. But it's not modular nor compatible with current efforts
>>>like 2.4 cardbus or 2.4 hotplug pci or 2.5 device mode. If one cannot
>>>do
>>> modprobe piix4_ide
>>>and have the right things happen automatically, the system is not
>>>modular. If it doesn't use the PCI API, it's implementing CardBus
>>>support in a non-standard way if at all.
>>>
>>Now what happens if you have more than one HOST of the same kind or the
>>"SAME HOST" with multiple functions but are really one HOST?
>>
>>I do not see how this will handle the problem.
>>But obviously I have been to far down making sure the DATA got to platter
>>correct and most likely missed a few things. :-/
>>
>>
>>>>>This is need for transparented support for cardbus and hotplug PCI, not
>>>>>
>>>>This is HOST level operation not DEVICE, and you do not see the differenc.
>>>>
>>>I do. I am talking about a HOST api here.
>>>
>>Okay we are getting some place now, cause what I was reading and seeing in
>>the changes registers a DRIVE to the PCI API and not a HOST.
>>
>
> Yes... I think there was some earlier confusion. PCI API is definitely
> an API for registering hosts.
>
> If you have a C structure "struct drive", it may be useful to have a
> pointer to struct pci_dev. That is just a reference from drive back to
> the host. So you could do crazy references like this pseudocode:
>
> struct pci_dev *host_pci;
> struct ata_host *host_ata;
> struct ata_channel *channel;
>
> host_pci = cur_drive->pci_dev;
> host_ata = pci_get_drvdata(host_pci);
> channel = &host_ata->channels[cur_drive->channel_number];
>
> These back-references are very useful, and use of a concept like this
> may be the source of confusion.

BTW.> The ATA driver is currently entierly confused about
hosts and channels. Usually a host has two channels on it but it
doesn't deal properly with this fact. (to ide_hwif_t instances... and a
"mate" pointer)