From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753352AbdDJLE3 (ORCPT ); Mon, 10 Apr 2017 07:04:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44818 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753245AbdDJLEZ (ORCPT ); Mon, 10 Apr 2017 07:04:25 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2814661D07 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=hdegoede@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 2814661D07 Subject: Re: [RFC] Fix shared irq trigger-flags conflict when old irqaction uses IRQF_TRIGGER_NONE To: Marc Zyngier , Thomas Gleixner References: <20170409195918.20864-1-hdegoede@redhat.com> <8e5511ce-601b-bde9-cdd3-c901ffc3d53d@arm.com> Cc: linux-acpi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org From: Hans de Goede Message-ID: <1117548f-9b5a-111c-6657-79a6c30179de@redhat.com> Date: Mon, 10 Apr 2017 13:04:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <8e5511ce-601b-bde9-cdd3-c901ffc3d53d@arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 10 Apr 2017 11:04:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org HI, On 10-04-17 12:13, Marc Zyngier wrote: > Hi Hans, > > On 09/04/17 20:59, Hans de Goede wrote: >> While writing a driver for the INT0002 ACPI device found on Intel >> Bay and Cherry Trail devices I hit the following error: >> >> "genirq: Flags mismatch irq 9. 00000084 (INT0002) vs. 00000080 (acpi)" >> >> This is caused by drivers/acpi/osl.c first doing: >> >> request_irq(irq, acpi_irq, IRQF_SHARED, "acpi", acpi_irq) >> >> While the irqdata for the irq contains no trigger flags, resulting >> in an irqaction with IRQF_TRIGGER_NONE. >> >> And then the INT0002 driver I'm working on calling platform_get_irq >> which does: irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); >> >> And then request_irq(irq, ..., IRQF_SHARED, ...) on the irq returned >> by platform_get_irq causes the error quoted above. >> >> Arguably the genirq code should not hit the shared irq trigger-flags >> mismatch code if the old irqaction has IRQF_TRIGGER_NONE as flags. >> >> This patch is an attempt at fixing this, but I'm not sure it is the >> right fix, hence it RFC status. >> >> Signed-off-by: Hans de Goede >> --- >> kernel/irq/manage.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >> index a4afe5c..24e5eef 100644 >> --- a/kernel/irq/manage.c >> +++ b/kernel/irq/manage.c >> @@ -1212,8 +1212,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) >> * set the trigger type must match. Also all must >> * agree on ONESHOT. >> */ >> + unsigned int old_msk = old->flags & IRQF_TRIGGER_MASK; >> + >> + if (!old_msk) >> + old_msk = irqd_get_trigger_type(&desc->irq_data); >> + >> if (!((old->flags & new->flags) & IRQF_SHARED) || >> - ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) || >> + ((old_msk ^ new->flags) & IRQF_TRIGGER_MASK) || >> ((old->flags ^ new->flags) & IRQF_ONESHOT)) >> goto mismatch; >> >> > > I'm afraid you're just papering over the issue here, as you leave the > "old" descriptor in an inconsistent state w.r.t. the "new" descriptor. > > My view is that the old irq_desc should be "upgraded" to the new trigger > configuration, because they are sharing a line and must have compatible > behaviours. There is no old irq_desc only an old ircaction, but yes that can easily be updated to reflect the mask from the irq_data, or maybe we should not use the oldaction for the trigger_mask bits at all and instead use the trigger_mask from the irq_data as done in: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/kernel/irq/manage.c?id=7ee7e87dfb158e79019ea1d5ea1b0e6f2bc93ee4 For a different code path ? Thomas? > NONE is effectively a wildcard, and the second interrupt > request should turn this wildcard into the real thing. > > The opposite case also exists (request a LEVEL interrupt first, then a > NONE), and should be resolved the same way (NONE becomes LEVEL). The 2nd order of requesting irqs will already work because of: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/kernel/irq/manage.c?id=4b357daed698c95d6b5eacc1c3c4afa206071ba2 Where the new_action trigger_mask gets filled with the triger_mask from the irq_data, which is a further hint that looking at irqd_get_trigger_type(&desc->irq_data) rather then at (old->flags IRQF_TRIGGER_MASK) is probably the right fix. Note btw that 4b357daed698 is (part of) what is breaking things for my use-case, I request the irq with IRQF_TRIGGER_NONE but 4b357daed698 modifies that before comparing the new trigger flags to the old. Regards, Hans