From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Tue, 31 Jul 2018 09:01:12 +0100 From: Russell King - ARM Linux To: Thomas Gleixner Cc: Bjorn Helgaas , Heiner Kallweit , Bjorn Helgaas , linux-pci@vger.kernel.org, Christoph Hellwig , linux-kernel@vger.kernel.org, MyungJoo Ham , Chanwoo Choi , Sebastian Reichel , Milo Kim , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Lee Jones Subject: Re: [PATCH] PCI: let pci_request_irq properly deal with threaded interrupts Message-ID: <20180731080111.GG17271@n2100.armlinux.org.uk> References: <20180730213028.GC45322@bhelgaas-glaptop.roam.corp.google.com> <20180730224252.GE45322@bhelgaas-glaptop.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: Russell King - ARM Linux List-ID: On Tue, Jul 31, 2018 at 12:50:21AM +0200, Thomas Gleixner wrote: > On Mon, 30 Jul 2018, Bjorn Helgaas wrote: > > > [+cc maintainers of possibly erroneous callers of request_threaded_irq()] > > > > On Mon, Jul 30, 2018 at 04:30:28PM -0500, Bjorn Helgaas wrote: > > > [+cc Thomas, Christoph, LKML] > > > > > > On Mon, Jul 30, 2018 at 12:03:42AM +0200, Heiner Kallweit wrote: > > > > If we have a threaded interrupt with the handler being NULL, then > > > > request_threaded_irq() -> __setup_irq() will complain and bail out > > > > if the IRQF_ONESHOT flag isn't set. Therefore check for the handler > > > > being NULL and set IRQF_ONESHOT in this case. > > > > > > > > This change is needed to migrate the mei_me driver to > > > > pci_alloc_irq_vectors() and pci_request_irq(). > > > > > > > > Signed-off-by: Heiner Kallweit > > > > > > I'd like an ack from Thomas because this requirement about IRQF_ONESHOT > > > usage isn't mentioned in the request_threaded_irq() function doc or > > > Documentation/ > > > > Possibly these other request_threaded_irq() callers are similarly > > broken? I can't tell for sure about tda998x_create(), but all the > > others certainly call request_threaded_irq() with "handler == NULL" > > and irqflags that do not contain IRQF_ONESHOT: > > > > tda998x_create() > > request_threaded_irq(client->irq, NULL, ..., irqd_get_trigger_type(), ...) > > (I can't tell what irqd_get_trigger_type() does) > > It reads the trigger type back from the irq chip (level/edge/polarity) but > does not return with the ONESHOT bit set. What tree are you (Bjorn) using there? Looking in my git history, request_threaded_irq() was added in January 2014, as: + irqf_trigger = + irqd_get_trigger_type(irq_get_irq_data(client->irq)); + ret = request_threaded_irq(client->irq, NULL, + tda998x_irq_thread, + irqf_trigger | IRQF_ONESHOT, + "tda998x", priv); and updated more recently for the CEC support in ae81553c30ef ("drm/i2c: tda998x: allow interrupt to be shared") to be: - irqf_trigger = + irq_flags = irqd_get_trigger_type(irq_get_irq_data(client->irq)); + irq_flags |= IRQF_SHARED | IRQF_ONESHOT; ret = request_threaded_irq(client->irq, NULL, - tda998x_irq_thread, - irqf_trigger | IRQF_ONESHOT, + tda998x_irq_thread, irq_flags, "tda998x", priv); In all cases, IRQF_ONESHOT has been set for this threaded interrupt. I've also checked drm-next, and it doesn't show anything like what Bjorn quoted. Confused. Bjorn, can you double check that what you think are erroneous request_threaded_irq() calls are actually as per what you quoted please? -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up