From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] pata_sl82c105: wrong assumptions about compatible PIO modes Date: Tue, 30 Jan 2007 22:08:12 +0300 Message-ID: <45BF979C.80200@ru.mvista.com> References: <200701302040.30895.sshtylyov@ru.mvista.com> <20070130190759.3d941365@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from gateway-1237.mvista.com ([63.81.120.155]:34740 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750896AbXA3TIP (ORCPT ); Tue, 30 Jan 2007 14:08:15 -0500 In-Reply-To: <20070130190759.3d941365@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cc: jgarzik@pobox.com, linux-ide@vger.kernel.org Hello. Alan wrote: >>Fix the wrong "compatible" PIO mode choices: MWDMA0 has 480 ns cycle while PIO1 >>only has 383 ns cycle, and MWDMA2 timings matchs those of PIO4 exactly. > Thanks for all this review work Oh, I've only started but there's too much to do elsewhere... :-) >>Frankly speaking, I'm not sure this function is useful or correct at all -- >>with the DMA timings being actually programmed in sl82c105_bmdma_start()... > It ought to be right > - bmdma_start loads the real DMA mode > - set_dmamode/set_piomode load the right PIO timings You just said set_piomode() is called before set_dmamode() by the libata core anyway -- there seems to be no point in re-writing the modes until the actual DMA is started. > - bmdma_stop restores the right PIO timings >>And the issue of the same registers being used for both PIO and DMA timings is >>not specific for this driver at all but seems to be addressed only by it... > For most drivers (those using the ata_timing interface) the timing merge > is done by ata_timing_compute(). Ah... >>Signed-off-by: Sergei Shtylyov > Acked-by: Alan Cox MBR, Sergei