From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH v2 -rt] ide: workaround buggy hardware issues with preemptable hardirqs Date: Sat, 28 Jun 2008 15:52:02 +0400 Message-ID: <486625E2.2020808@ru.mvista.com> References: <20080623234037.GA6793@polina.dev.rtsoft.ru> <20080623235141.GB17297@elte.hu> <20080624000016.GA12547@polina.dev.rtsoft.ru> <20080625123431.GA25452@polina.dev.rtsoft.ru> <20080628005436.GA1956@polina.dev.rtsoft.ru> <486612CC.3060505@ru.mvista.com> <20080628113126.GA438@polina.dev.rtsoft.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from gateway-1237.mvista.com ([63.81.120.155]:39033 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750736AbYF1LwL (ORCPT ); Sat, 28 Jun 2008 07:52:11 -0400 In-Reply-To: <20080628113126.GA438@polina.dev.rtsoft.ru> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: avorontsov@ru.mvista.com Cc: Ingo Molnar , linux-ide@vger.kernel.org, Bartlomiej Zolnierkiewicz , Alan Cox , linux-kernel@vger.kernel.org, Thomas Gleixner , Steven Rostedt , Daniel Walker Hello. Anton Vorontsov wrote: >>> But some hardware (namely ULi M5228 in the ULi M1575 "Super South Brige") >>> behaves in a strange way: it asserts interrupts as edge sensitive. And >>> because preemptable IRQ handler disables PIC's interrupt, PIC will likely >>> miss it. >>> >>> >> Unmasking an IRQ should re-enable an edge detector in a PIC (or that >> detector should even be independent from mask). >> > Should? Hm.. well, I can easily check it. Will just program the MPIC IRQ > to edge sensitive, and see if it fixes the problem (not sure if I already > tried this, I think I did try). > That will not help if edge detector is not active for masked out IRQs (that's how i8259 behaves, IIRC) *and* you're getting the short IRQ "pulses" but should help if IRQ is generated normally -- though in this case the level trigger mode (with the same polarity) should work as well... MBR, Sergei