From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: [PATCH 54/64] alim15x3: fix handling of UDMA enable bit Date: Tue, 13 Apr 2010 17:15:06 +0200 Message-ID: <201004131715.06225.bzolnier@gmail.com> References: <20100118171349.14623.90030.sendpatchset@localhost> <20100118172126.14623.55960.sendpatchset@localhost> <4BC325D8.9040607@ru.mvista.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from fg-out-1718.google.com ([72.14.220.153]:10143 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983Ab0DMPQH (ORCPT ); Tue, 13 Apr 2010 11:16:07 -0400 In-Reply-To: <4BC325D8.9040607@ru.mvista.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Sergei Shtylyov Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hi Sergei, On Monday 12 April 2010 03:53:28 pm Sergei Shtylyov wrote: > Bartlomiej Zolnierkiewicz wrote: > > From: Bartlomiej Zolnierkiewicz > > Subject: [PATCH] alim15x3: fix handling of UDMA enable bit > > > > Clear UDMA enable bit also for PIO modes. > > > > Sorry for late mail but I fail to understand why this was done and > what this patch fixes. > > > Based on libata pata_ali host driver. > > libata has different mode programming code where first always the PIO > mode and then DMA mode is set. With IDE core, the order can be > different, PIO mode programming shouldn't affect DMA mode bits -- and > does not affect it in the other drivers... This was just a tiny part of larger patchset preparing alim15x3 for conversion to ide2libata framework and it seems the problem is only affecting user-initiated transfer mode changes (which are strongly discouraged anyway) as both libata and IDE core use quite similar transfer mode programming sequence by default. However thanks for noticing the issue, I will fix it for both drivers during the next update of atang tree (unless somebody sends me a patch sooner). -- Bartlomiej Zolnierkiewicz