From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753897Ab2IMAnN (ORCPT ); Wed, 12 Sep 2012 20:43:13 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:37074 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755205Ab2ILXav (ORCPT ); Wed, 12 Sep 2012 19:30:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , Jon Hunter , Kevin Hilman , Tony Lindgren Subject: [ 008/108] ARM: OMAP2+: Fix dmtimer set source clock failure Date: Wed, 12 Sep 2012 16:28:06 -0700 Message-Id: <20120912232451.310834782@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120912232450.500619493@linuxfoundation.org> References: <20120912232816.GA1655@kroah.com> <20120912232450.500619493@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jon Hunter commit 54f32a35f4d3a653a18a2c8c239f19ae060bd803 upstream. Calling the dmtimer function omap_dm_timer_set_source() fails if following a call to pm_runtime_put() to disable the timer. For example the following sequence would fail to set the parent clock ... omap_dm_timer_stop(gptimer); omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_32_KHZ); The following error message would be seen ... omap_dm_timer_set_source: failed to set timer_32k_ck as parent The problem is that, by design, pm_runtime_put() simply decrements the usage count and returns before the timer has actually been disabled. Therefore, setting the parent clock failed because the timer was still active when the trying to set the parent clock. Setting a parent clock will fail if the clock you are setting the parent of has a non-zero usage count. To ensure that this does not fail use pm_runtime_put_sync() when disabling the timer. Note that this will not be seen on OMAP1 devices, because these devices do not use the clock framework for dmtimers. Signed-off-by: Jon Hunter Acked-by: Kevin Hilman Signed-off-by: Tony Lindgren Signed-off-by: Greg Kroah-Hartman --- arch/arm/plat-omap/dmtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm/plat-omap/dmtimer.c +++ b/arch/arm/plat-omap/dmtimer.c @@ -236,7 +236,7 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_enable); void omap_dm_timer_disable(struct omap_dm_timer *timer) { - pm_runtime_put(&timer->pdev->dev); + pm_runtime_put_sync(&timer->pdev->dev); } EXPORT_SYMBOL_GPL(omap_dm_timer_disable);