Hello. James Bottomley wrote:
I can get all of this working by fixing up all the hard coded knowledge in libata-sff only to use a single port. However, I can't fix the libata-sff driver until I know how to tell there's only one port wired. Does anyone with cmd649 knowledge have any idea how I might tell this?
The secondary port is enabled in the PCI config. space: register 0x51 bit 3 controls this. Unfortunately, pata_cmd64x driver still doesn't check the channel enable bits; the cmd64x driver does though, so it might be worth trying...
So this is the enablebits code in driver/ide
We still need to ensure that these are indeed the enable bits that are at play here...
that's missing from any of the libata stuff?
Not from any. It's handled in some drivers, like pata_hpt37x, for example -- in their prereset() methods.
Should this be generic in libata-sff? ...
There's even libata core function, pci_test_config_bits() that facilitates this check.
I mean even on an x86 where arbitrary memory can be poked without consequence, trying to activate a disabled port will still produce lots of noise.
The story with pata_cmd64x is somewhat convoluted: originally (when the libata driver was created) in the IDE driver there were only enable bits for the secondary channel of PCI0646 (and even those wrong); I fixed those and added the enable bits for other chips back in 2007 but it never got propagated to pata_cmd64x. Well, I have some plans for changes to this driver but not much time to actually do them currently...
James
WBR, Sergei