From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Clark Subject: Re: Kernel 2.6.37 erroneously limiting to UDMA/33 Date: Thu, 06 Jan 2011 10:29:30 -0500 Message-ID: <4D25DFDA.8010909@earthlink.net> References: <20110106103035.GA3484@rhlx01.hs-esslingen.de> Reply-To: sclark46@earthlink.net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from elasmtp-scoter.atl.sa.earthlink.net ([209.86.89.67]:52756 "EHLO elasmtp-scoter.atl.sa.earthlink.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753035Ab1AFP3d (ORCPT ); Thu, 6 Jan 2011 10:29:33 -0500 In-Reply-To: <20110106103035.GA3484@rhlx01.hs-esslingen.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Andreas Mohr Cc: Robert Hancock , linux-kernel , ide On 01/06/2011 05:30 AM, Andreas Mohr wrote: > Hi, > > Robert Hancock wrote: > >> On 01/05/2011 12:33 PM, Stephen Clark wrote: >> >>> Hello, >>> >>> Why is the kernel limiting me to udma/33 when the device says it can do >>> ata2.01: CFA: TRANSCEND, 20070831, max UDMA/66 >>> >>> There is no cable the compact flash is a socket on the motherboard! >>> >> The kernel has no way to know that, and presumably the board isn't >> connecting the signal for IDE pin 34 to ground in order to properly >> signal that an 80-wire cable (or equivalent) is connected so that speeds >> over UDMA33 can be used. >> >> You should be able to use the libata.force=80c option on the kernel >> command line to override the cable detection. >> > Further comments for the OP: > > If 80c happens to be correct for this machine (since it's soldered > it's quite obvious) and the machine is quite wide-spread, perhaps one needs > to add overrides within drivers/ata/pata_via.c/via_cable_detect() functionality, > analogous to the ata_piix.c/ich_pata_cable_detect() case where it uses > an entire ich_laptop device list to match against, > to detect special 80c compatible cases. > > But since pata_via.c has the insightful comment > "Perform cable detection. Actually for the VIA case the BIOS > already did this for us." > it looks like your BIOS might be considered "broken" > due to not indicating 80c for such a solder job > --> BIOS upgrade available? > > Will check. The machine is an Acrosser AR-M0898B micro box, for use such as a firewall, vpn appliance, etc. > And perhaps better avoid mentioning a specific kernel in the subject > line unless it's a regression (which likely isn't the case here), > or write it like "..... (on 2.6.XXX)". > > Good point. > Andreas Mohr > > -- "They that give up essential liberty to obtain temporary safety, deserve neither liberty nor safety." (Ben Franklin) "The course of history shows that as a government grows, liberty decreases." (Thomas Jefferson)