From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757564AbZEVTS2 (ORCPT ); Fri, 22 May 2009 15:18:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756903AbZEVTST (ORCPT ); Fri, 22 May 2009 15:18:19 -0400 Received: from h155.mvista.com ([63.81.120.155]:41818 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751463AbZEVTSS (ORCPT ); Fri, 22 May 2009 15:18:18 -0400 Message-ID: <4A16FAB0.5020301@ru.mvista.com> Date: Fri, 22 May 2009 23:19:12 +0400 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Bartlomiej Zolnierkiewicz Cc: linux-m68k@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: ->ack_intr in m68k IDE drivers [was: Re: [PATCH 2/5] ide: ->ide_dma_clear_irq() -> ->clear_irq()] References: <200808192031.40288.bzolnier@gmail.com> <48CEDD89.5060107@ru.mvista.com> <4A15600A.40906@ru.mvista.com> <200905222044.42688.bzolnier@gmail.com> In-Reply-To: <200905222044.42688.bzolnier@gmail.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bartlomiej Zolnierkiewicz wrote: >>>> It may also be worth considering turning this method into >>>>test-and-clear, so that we can get the actual IDE interrupt state on >>>>the chips that implement this... >>> Probably might add the test_irq() method to be called on >>>!hwif->waiting_for_dma. Cleraing the status at once seems impractical... >> Yet this seems what ack_intr() method is doing already... >> What it does is testing IRQ status and "acknowledging" it (the semantics >>of "acknowledge" is not clear to me, yet it seems that it's clearing the >>interrupt latch in the drivers where it's implemented). And the call site of >>ack_intr() method corresponds to where test_irq() should have been called, >>so it seems we don't need yet another method and probably didn't even need >>clear_irq() method in the first place?.. > They have different goals -- the main purpose of ack_intr() (despite its name) > seems to be testing whether the IRQ is ours, It does clear some interrupt bit if it sees that IRQ is ours too, hence the same. > OTOH in clear_irq() we know that > already and we just want to clear the pending IRQ status. There seems to be duplication of functionality b/w ack_intr() and clear_irq() now... > So I'm not sure if unification is desirable... though some improvements are > definitely possibly there (less confusing naming at least)... >> Bart, could you clarify about how ack_intr() is supposed to work? > Good question, m68k list would be the best place to look for an answer.. Well, I seem to have been able to infer it from the code... MBR, Sergei