Re: SATA RAID5 speed drop of 100 MB/s

[Carlo Wood]

For what it's worth... I tried applying

--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -516,6 +516,8 @@ static void ahci_save_initial_config(struct pci_dev *pdev,
         * reset.  Values without are used for driver operation.
         */
        hpriv->saved_cap = cap = readl(mmio + HOST_CAP);
+       hpriv->saved_cap &= ( (1<<28) | (1<<17) );
+       hpriv->saved_cap |= (1 << 27);
        hpriv->saved_port_map = port_map = readl(mmio + HOST_PORTS_IMPL);

        /* some chips lie about 64bit support */

to 2.6.22-rc5, but it had no effect :*)

I'll await any comments from a kernel developer for now.
Please let me know if you want me to test something.

-- 
Carlo Wood <carlo@xxxxxxxxxx>
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