Re: [PROBLEM + PATCH] Sata port disabled by BIOS gets initialized by ata_piix drive

[Tejun Heo <htejun@gmail.com>]

shyam_iyer@dell.com wrote:
> Problem Sata disks are connected to onboard sata ports of PowerEdge
> 1900 (ESB2 southbridge chipset). If one of the port is disabled in
> the bios then they get enabled again by the ata_piix driver because
> of a default port map being written to the Port control and status
> register(0x91-93). Instead the driver should preserve the bios
> setting by way of a fix like this.

What happens if the port is enabled by the kernel?

> Fix: The BIOS configured PCS value must be anded logically with the
> default port map for the chipset. This way the BIOS information will
> not be lost by the reinitialization of the config space by the
> ata_piix driver. The below patch is against 2.6.21 kernel.

I'm not sure whether this is a good idea and it has potential to break a
lot of other configurations.  That part of code is used for *all*
ata_piix out there, so we need a really really good reason to change
that.  So, please explain what you're trying to fix better.

-- 
tejun