From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: unexpected downspeed of AHCI controller on Intel Seaburg 5400 Date: Mon, 24 Nov 2008 14:18:10 +0900 Message-ID: <492A3912.3060305@kernel.org> References: <6.2.5.6.2.20081118154009.01c8a2d0@binnacle.cx> <4923743A.2050903@shaw.ca> <6.2.5.6.2.20081118210621.01d6c680@binnacle.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:45001 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750701AbYKXFSQ (ORCPT ); Mon, 24 Nov 2008 00:18:16 -0500 In-Reply-To: <6.2.5.6.2.20081118210621.01d6c680@binnacle.cx> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: starlight@binnacle.cx Cc: linux-ide@vger.kernel.org starlight@binnacle.cx wrote: > Is it possible for the BIOS to tell the chip to not negogiate > above 1.5 Gbps? I'm wondering if HP might have done this to > prevent the bug below from happening. If so it would be > nice for the driver to put it back to 3 Gbps. The standard way to put that limit is to use SControl but it isn't doing that, as far as ahci is concerned, it's free to negotiate any speed but is negotiating 1.5Gbps. Maybe they capped using some hidden register to workaround the erratum. At any rate, it doesn't really matter unless you're gonna hang multiple devices to a single port using PMP. Thanks. -- tejun