From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Edwards Subject: Re: What to set uart_port->irq to for polled driver? Date: Thu, 28 Feb 2013 20:42:39 +0000 (UTC) Message-ID: References: <1362076338.3337.3.camel@thor.lan> <1362082593.3337.16.camel@thor.lan> Return-path: Received: from plane.gmane.org ([80.91.229.3]:45679 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754751Ab3B1Umy (ORCPT ); Thu, 28 Feb 2013 15:42:54 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1UBAJs-0004vZ-TD for linux-serial@vger.kernel.org; Thu, 28 Feb 2013 21:43:12 +0100 Received: from dsl.comtrol.com ([64.122.56.22]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 28 Feb 2013 21:43:12 +0100 Received: from grant.b.edwards by dsl.comtrol.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 28 Feb 2013 21:43:12 +0100 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org On 2013-02-28, Peter Hurley wrote: > On Thu, 2013-02-28 at 18:43 +0000, Grant Edwards wrote: >> On 2013-02-28, Peter Hurley wrote: >>> On Wed, 2013-02-13 at 15:24 +0000, Grant Edwards wrote: >>>> For a polled serial driver that doesn't use interrupts, to what should >>>> the "irq" field in the uart_port structure be set? Should it be 0? >>>> Should it be the unused IRQ associated with the PCI card slot in which >>>> the board is found? >>> >>> Doesn't look supported, but adding the support doesn't look >>> difficult. At the very least, a patch is required so that on port >>> shutdown, the core doesn't synchronize_irq(). >> >> Does the call ty synchronize_irq() do any harm? AFAICT, it will just >> cause a short delay if handling of that IRQ is in-progress. >> >> I currently set the "irq" field to the IRQ number that would be used >> by the board if I did choose to enable interrupts. That seems to work >> fine (with rather limited testing). > > AFAICT, it's probably ok; but it might not be. Certainly more robust > to just add a UPF_POLLING flag and skip the synchronize_irq(). > > Is this an in-tree driver? No. One of my polled mode drivers is an enhanced version of the new rp2 serial driver. It's currently in beta test. I posted a snapshot of that one to this list last week, but it hasn't been submitted as a git patch yet. The other is a rewrite of the rocket driver -- it's still under development. I'd be happy to submit it for inclusion in the tree when it's done. -- Grant Edwards grant.b.edwards Yow! Give them RADAR-GUIDED at SKEE-BALL LANES and gmail.com VELVEETA BURRITOS!!