Messages in this thread |  | | | Date | Tue, 02 Jan 2007 16:29:00 -0500 | | From | Jeff Garzik <> | | Subject | Re: [PATCH] libata: fix combined mode (was Re: Happy New Year (and v2.6.20-rc3 released)) |
| |
Alan wrote: >>> This is a silly complaint because the SFF layer in libata doesn't handle >>> this case yet anyway. >> Yes, it's "silly" people people use configurations you find inconvenient. >> >> At least one embedded x86 case cares, that I know of. They only needed >> to make two minor changes to make it work. > > *It is not part of 2.6.20* > >> The code no long reserves resources for the "extra" PCI BAR that often >> exists on PCI controllers regardless of legacy/native mode. Previously, >> the code called pci_request_regions() to reserve ALL regions attached to >> the PCI device. > > We use BAR5 on two devices in legacy mode. Both of those reserve all the > other resources.
Translation: You want to hand-wave away an obvious regression that YOU have created with your fix-to-a-fix.
> We can fix BAR5 in .21 when all the combined mode crap > goes away.
Translation: Problems disappear in 2.6.21 because Jeff will revert the code I touched to its previous state -- always calling pci_request_regions() -- and all the problems I introduced by avoiding pci_request_regions() will go away.
Why INTRODUCE these 2.6.20 Alan-isms, if they are going away in 2.6.21?
>> You have suddenly decided that it's OK to --not reserve at all-- these >> additional regions. > > It's not ideal - but it is perfectly sufficient for 2.6.20 > >> Proof: The AHCI PCI BAR (#5, zero-based) is clearly NOT reserved, even >> though we talk to it, in piix_disable_ahci() of ata_piix.c. > > We always claim the other BARs so catch a collision.
Where? AFAICS, it is crystal clear the behavior:
* Prior to your patch, ata_piix in legacy mode calls pci_request_regions() to intentionally reserve ALL regions on the PCI device.
* After your patch, the code explicitly calls pci_request_region() for BARs 0-4, but never for BAR5.
Another driver is now free to claim a PCI BAR, and start running the hardware in AHCI mode, whee!
Jeff
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |