Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935782Ab3DINeh (ORCPT ); Tue, 9 Apr 2013 09:34:37 -0400 Received: from mail-bk0-f41.google.com ([209.85.214.41]:48173 "EHLO mail-bk0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759206Ab3DINef (ORCPT ); Tue, 9 Apr 2013 09:34:35 -0400 MIME-Version: 1.0 In-Reply-To: References: <1365500744-14839-1-git-send-email-gautam.vivek@samsung.com> <5163E8EB.1050803@samsung.com> Date: Tue, 9 Apr 2013 19:04:34 +0530 Message-ID: Subject: Re: [PATCH RFC] rtc: rtc-s3c: use clk_prepare_enable and clk_disable_unprepare From: Vivek Gautam To: Sylwester Nawrocki Cc: Vivek Gautam , rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, a.zummo@towertech.it, kgene.kim@samsung.com, dianders@chromium.org, Thomas Abraham Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6148 Lines: 115 Hi Sylwester, On Tue, Apr 9, 2013 at 6:21 PM, Vivek Gautam wrote: > Hi Sylwester, > > > On Tue, Apr 9, 2013 at 3:39 PM, Sylwester Nawrocki > wrote: >> On 04/09/2013 11:45 AM, Vivek Gautam wrote: >>> Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare >>> calls as required by common clock framework, to get rid of >>> WARN_ON on prepare_count. >> >> Hmm, do you think warnings like below are any better that WARN_ON() on wrong >> clock's prepare_count value ? :) >> >>> Signed-off-by: Vivek Gautam >>> --- >>> >>> This fixes the warnings in the boot log coming out of enabling >>> the common clock framework in exynos platform. >>> >>> However, on doing system suspend/resume using rtc wake mechanism >>> we still get following warning dump for the first time we suspend >>> using commands: >>> echo +10 > /sys/class/rtc/rtc0/wakealarm >>> echo mem > /sys/power/state >>> >>> [ 12.530000] ------------[ cut here ]------------ >>> [ 12.530000] WARNING: at kernel/mutex.c:199 __mutex_lock_slowpath+0x2c0/0x340() >>> [ 12.530000] Modules linked in: >>> [ 12.530000] [<80014c60>] (unwind_backtrace+0x0/0xf8) from [<8001ebd0>] (warn_slowpath_common+0x54/0x68) >>> [ 12.530000] [<8001ebd0>] (warn_slowpath_common+0x54/0x68) from [<8001ec00>] (warn_slowpath_null+0x1c/0x24) >>> [ 12.530000] [<8001ec00>] (warn_slowpath_null+0x1c/0x24) from [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) >>> [ 12.530000] [<8033f548>] (__mutex_lock_slowpath+0x2c0/0x340) from [<8033f5d4>] (mutex_lock+0xc/0x24) >>> [ 12.530000] [<8033f5d4>] (mutex_lock+0xc/0x24) from [<80299e18>] (clk_prepare+0x18/0x34) >>> [ 12.530000] [<80299e18>] (clk_prepare+0x18/0x34) from [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) >>> [ 12.530000] [<802862d8>] (s3c_rtc_alarmirq+0x1c/0x98) from [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) >>> [ 12.530000] [<8006ad78>] (handle_irq_event_percpu+0x54/0x194) from [<8006aef4>] (handle_irq_event+0x3c/0x5c) >>> [ 12.530000] [<8006aef4>] (handle_irq_event+0x3c/0x5c) from [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) >>> [ 12.530000] [<8006db00>] (handle_fasteoi_irq+0xa4/0x134) from [<8006a594>] (generic_handle_irq+0x30/0x40) >>> [ 12.530000] [<8006a594>] (generic_handle_irq+0x30/0x40) from [<8000f4fc>] (handle_IRQ+0x40/0x90) >>> [ 12.530000] [<8000f4fc>] (handle_IRQ+0x40/0x90) from [<80008544>] (gic_handle_irq+0x38/0x68) >>> [ 12.530000] [<80008544>] (gic_handle_irq+0x38/0x68) from [<8000e200>] (__irq_svc+0x40/0x70) >>> [ 12.530000] Exception stack(0x8182be60 to 0x8182bea8) >>> [ 12.530000] be60: 00000000 00000000 0000000c ffffffff 60000013 8049fc50 00000000 80479a10 >>> [ 12.530000] be80: 60000013 ee97de98 804799c0 00000001 0000000d 8182bea8 803412dc 803412e0 >>> [ 12.530000] bea0: 60000013 ffffffff >>> [ 12.530000] [<8000e200>] (__irq_svc+0x40/0x70) from [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) >>> [ 12.530000] [<803412e0>] (_raw_spin_unlock_irqrestore+0x10/0x38) from [<80070bc4>] (resume_irqs+0x9c/0xb8) >>> [ 12.530000] [<80070bc4>] (resume_irqs+0x9c/0xb8) from [<8021d528>] (dpm_resume_start+0xc/0x18) >>> [ 12.530000] [<8021d528>] (dpm_resume_start+0xc/0x18) from [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) >>> [ 12.530000] [<800544ac>] (suspend_devices_and_enter+0x118/0x2e4) from [<80054814>] (pm_suspend+0x19c/0x214) >>> [ 12.530000] [<80054814>] (pm_suspend+0x19c/0x214) from [<80053a58>] (state_store+0x120/0x12c) >>> [ 12.530000] [<80053a58>] (state_store+0x120/0x12c) from [<801ae9d8>] (kobj_attr_store+0x14/0x20) >>> [ 12.530000] [<801ae9d8>] (kobj_attr_store+0x14/0x20) from [<801092c8>] (sysfs_write_file+0xfc/0x17c) >>> [ 12.530000] [<801092c8>] (sysfs_write_file+0xfc/0x17c) from [<800b0d84>] (vfs_write+0xa8/0x138) >>> [ 12.530000] [<800b0d84>] (vfs_write+0xa8/0x138) from [<800b10e4>] (sys_write+0x40/0x68) >>> [ 12.530000] [<800b10e4>] (sys_write+0x40/0x68) from [<8000e600>] (ret_fast_syscall+0x0/0x30) >>> [ 12.530000] ---[ end trace 8643216fba2e8cb5 ]--- >>> >>> drivers/rtc/rtc-s3c.c | 58 ++++++++++++++++++++++++------------------------ >>> 1 files changed, 29 insertions(+), 29 deletions(-) >>> >>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c >>> index fb994e9..75637ad 100644 >>> --- a/drivers/rtc/rtc-s3c.c >>> +++ b/drivers/rtc/rtc-s3c.c >>> @@ -65,12 +65,12 @@ static void s3c_rtc_alarm_clk_enable(bool enable) >>> spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags); >>> if (enable) { >>> if (!alarm_clk_enabled) { >>> - clk_enable(rtc_clk); >>> + clk_prepare_enable(rtc_clk); >>> alarm_clk_enabled = true; >>> } >>> } else { >>> if (alarm_clk_enabled) { >>> - clk_disable(rtc_clk); >>> + clk_disable_unprepare(rtc_clk); >>> alarm_clk_enabled = false; >>> } >>> } >>> @@ -83,13 +83,13 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id) >>> { >>> struct rtc_device *rdev = id; >>> >>> - clk_enable(rtc_clk); >>> + clk_prepare_enable(rtc_clk); >> >> The reason for the above failure is that clk_prepare is called from an interrupt >> context. You are not supposed to use clk_prepare_enable()/clk_unprepare_disble() >> like this. Instead, prepare the clock in s3c_rtc_probe() and unprepare in the >> driver's remove() callback. And clk_enable()/clk_disable calls could stay untouched. > > Aah !! actually missed a similar patch from Thomas Abraham :( > doing the same as suggested by you. > Its available at: > http://patchwork.ozlabs.org/patch/188687/ There's a change required in the above mentioned patch, so possibly Thomas can go ahead and post the next version of that. -- Thanks & Regards Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/