From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] gpio/omap: fix wakeups on level-triggered GPIOs Date: Wed, 22 Feb 2012 10:00:45 -0800 Message-ID: <20120222180045.GW18185@atomide.com> References: <1329850878-22189-1-git-send-email-khilman@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:58028 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751966Ab2BVSAt (ORCPT ); Wed, 22 Feb 2012 13:00:49 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "DebBarma, Tarun Kanti" Cc: Kevin Hilman , Grant Likely , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org * DebBarma, Tarun Kanti [120222 08:46]: > On Wed, Feb 22, 2012 at 12:31 AM, Kevin Hilman wrote= : > > While both level- and edge-triggered GPIOs are capable of generatin= g > > interrupts, only edge-triggered GPIOs are capable of generating a > > module-level wakeup to the PRCM (c.f. 34xx NDA TRM section 25.5.3.2= =2E) > > > > In order to ensure that devices using level-triggered GPIOs as > > interrupts can also cause wakeups (e.g. from idle), this patch enab= les > > edge-triggering for wakeup-enabled, level-triggered GPIOs when a GP= IO > > bank is runtime-suspended (which also happens during idle.) > > > > This fixes a problem found in GPMC-connected network cards with GPI= O > > interrupts (e.g. smsc911x on Zoom3, Overo, ...) where network booti= ng > > with NFSroot was very slow since the GPIO IRQs used by the NIC were > > not generating PRCM wakeups, and thus not waking the system from id= le. > > NOTE: until v3.3, this boot-time problem was somewhat masked becaus= e > > the UART init prevented WFI during boot until the full serial drive= r > > was available. =C2=A0Preventing WFI allowed regular GPIO interrupts= to fire > > and this problem was not seen. =C2=A0After the UART runtime PM clea= nups, we > > no longer avoid WFI during boot, so GPIO IRQs that were not causing > > wakeups resulted in very slow IRQ response times. > > > > Tested on platforms using level-triggered GPIOs for network IRQs us= ing > > the SMSC911x NIC: 3530/Overo and 3630/Zoom3. > > > > Reported-by: Tony Lindgren > > Signed-off-by: Kevin Hilman >=20 > I have tested on OMAP3430 by making modification to touchscreen GPIO. > (I had similar change in my next planned cleanup/fix series.) > If needed you can add my Tested-by: Work for me too: Tested-by: Tony Lindgren -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html