From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] omap3: beagle: Use GPTIMERi 1 for clockevents Date: Mon, 27 Jun 2011 03:14:28 -0700 Message-ID: <20110627101427.GH23145@atomide.com> References: <1308932625-17632-1-git-send-email-premi@ti.com> <86CFE860-E18E-4B96-A753-11EB7C5C1C86@dominion.thruhere.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Paul Walmsley Cc: Koen Kooi , "Premi, Sanjeev" , linux-arm-kernel , "linux-omap@vger.kernel.org List" List-Id: linux-omap@vger.kernel.org * Paul Walmsley [110625 15:42]: > On Sun, 26 Jun 2011, Premi, Sanjeev wrote: > > > [sp] I didn't include a reason - because the problem may not > > be reproducible on the public trees. > > > > During tests performed in internal development trees, the > > BogoMIPS calculations @ 1GHz wouldn't go beyond "830-850" > > range. While there was no such inconsistency on OMAP3EVM. > > There are some other reasons to avoid GPTIMER12 when possible, which you > should probably put in the patch description. The most important, in my > view, is that the clock source for GPTIMER12 is much less frequency-stable > than the clock sources for GPTIMER1. So using GPTIMER12 can result in > major time skew over a fairly short interval. > > I've been meaning to send a patch like this for some time, so I'm happy to > see this fixed. This fix will cause bad dependency issues with sys_timer. This patch has a dependency to omap3_beagle_init_rev, which depends on the mux framework and gpio framework. Not cool for init_early. We just want to initialize sys_timer early without any complicated dependencies. The best way to fix this is to set a separate machine ID for the properly working beagle boards like xm, then just set the .timer entry to omap3_timer for working beagle boards and omap3_secure_timer for non-working beagle boards. The rest of the board-*.c file can be shared. The above assumes the patches in devel-timer branch where we no longer have the non-standard timer interface, but use the sys_timer entries instead like we should. Regards, Tony