From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5A6C2B6F81 for ; Fri, 2 Sep 2011 04:49:47 +1000 (EST) Subject: Re: [PATCH] powerpc/time: When starting the decrementer don't zero the other bits in TCR Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii From: Kumar Gala In-Reply-To: <4E5FA6ED.9010703@freescale.com> Date: Thu, 1 Sep 2011 13:49:39 -0500 Message-Id: <631F005F-2A4D-40E6-8C34-177F5CCAE40D@kernel.crashing.org> References: <1314274795-4966-1-git-send-email-Laurentiu.Tudor@freescale.com> <9A0167AA-E19D-4492-8D65-6FA4518ABE98@kernel.crashing.org> <4E5F42CE.1060502@freescale.com> <4E5FA6ED.9010703@freescale.com> To: Tudor Laurentiu Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sep 1, 2011, at 10:38 AM, Tudor Laurentiu wrote: > On 9/1/2011 4:56 PM, Kumar Gala wrote: >>=20 >> On Sep 1, 2011, at 3:31 AM, Tudor Laurentiu wrote: >>=20 >>> On 9/1/2011 9:27 AM, Kumar Gala wrote: >>>>=20 >>>> On Aug 25, 2011, at 7:19 AM, Laurentiu Tudor wrote: >>>>=20 >>>>> Clearing the other TCR bits might break code that sets them (e.g. = to setup >>>>> the watchdog or fixed interval timer) before = start_cpu_decrementer() gets >>>>> called. >>>>=20 >>>> Can you be more specific about the case you're concerned about. = I'm not sure we want to leave the FIT enabled if it was previously. = Watchdog I could possibly see leaving alone. >>>=20 >>> My particular case was this: I was experimenting with having the = watchdog enabled during the boot process, in case something goes wrong = before the normal watchdog mechanism kicks in. That didn't work without = making this modification. >>> Then, thinking that having a function start_cpu_decrementer() = touching the other timers and not only the decrementer as its name = implies might not be good. So I submitted this patch to the public = mailing list to let the community decide if it's useful. >>=20 >> So I think renaming the function is fine, and I think not touching = the watchdog bits is also reasonable. So if you update the patch along = those lines I think we can push in. I do want to make sure that the FIT = is disabled as we dont expect it. >=20 > how about: >=20 > static void setup_cpu_timers() >=20 > ? Sounds fine to me >=20 >> Probably add a comment about how care needs to be taken if the = wathchdog is enable be firmware or a previous kernel. >=20 > OK. >=20 >=20 >=20 > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev