On Wed, Apr 16, 2014 at 05:46:47PM -0500, Rob Herring wrote: > On Wed, Apr 16, 2014 at 3:43 AM, Russell King > <rmk+kernel@xxxxxxxxxxxxxxxx> wrote: > > Spread-spectrum doesn't work with Cubox-i hardware, so we have to > > disable this feature. Add a DT property so that platforms can > > indicate that this feature should not be enabled. > > This is for spread-spectrum tx or rx? Transmit SS is optional to > support, but the receiver must support SS. Otherwise random drives > won't work which makes for a good user experience. Is this really a > board quirk rather than a Si issue? No idea. This bit controls clock generation, and one reason given to disable it is if the reference clock being supplied is already spread spectrum. I don't think that applies here. It doesn't say which clock(s) this is applied to - I would guess it's the transmit clock. All I know is that with SS enabled, the drive is not detected, and SolidRun's original port disables SS. Disabling SS allows the external drive to be detected. I have no capability to check the eye pattern, so I've no idea if there's a problem with the electrical setup which stops SS from working. All I know is with the parameters I give here (which are those which SolidRun's original port uses) and with SS disabled, it works. -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
