[RFC] JS20 IDE perf patch

[Anton Blanchard]

Hi Doug,

Did this get sorted out or do we still need to fix it in 2.6?

Anton

On Mon, Dec 15, 2003 at 11:06:58AM -0600, Doug Maxey wrote:
>
> Howdy,
>
>   Have done some investigation of the AMD IDE implementation on the
>   JS20 and have come up with a set of patches to address this.  The
>   underlying assumption that the PCI bus can only do 66mhz is no
>   longer true with the HT implementation on this platform.
>
>   The specific issues seen were:
>   1) ide.c has code that assumes the PCI bus only runs between 20 and
>      66 mhz.
>   2) FW has not completely configured the chipset to run at the higher
>      IDE bus speeds.
>   3) amd74xx.c does not recognize and cannot use the higher PCI bus
>      speeds to enable the higher IDE speeds.
>
>   Item 1 is addressed by creating ATA_PCIMHZ_MIN and ATA_PCIMHZ_MAX in
>   linux/ide.h.  These values are used in ide/ide.c and amd74xx.c.  If
>   there are arch specific values, they override the the values set in
>   linux/ide.h via the arch specific header.
>
>   Item 2 is addressed by fixup_amd_ide in arch/ppc64/kernel/pci.c.
>
>   Item 3 uses the ATA_PCIMHZ* to calculate the PCI bus frequency in
>   amd74xx.c and is used to determine the UDMA settings for the
>   drives.
>
>   Please review these changes.  Comments are welcome.
>
> ++doug
>


** Sent via the linuxppc64-dev mail list. See http://lists.linuxppc.org/
** This list is shutting down 7/24/2004.