From mboxrd@z Thu Jan 1 00:00:00 1970 From: soren.brinkmann@xilinx.com (=?utf-8?B?U8O2cmVu?= Brinkmann) Date: Thu, 22 Aug 2013 16:38:48 -0700 Subject: [PATCH 1/2] tick: broadcast: Deny per-cpu clockevents from being broadcast sources In-Reply-To: <1377191201-14696-1-git-send-email-sboyd@codeaurora.org> References: <52138784.7050703@linaro.org> <1377191201-14696-1-git-send-email-sboyd@codeaurora.org> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Aug 22, 2013 at 10:06:40AM -0700, Stephen Boyd wrote: > On most ARM systems the per-cpu clockevents are truly per-cpu in > the sense that they can't be controlled on any other CPU besides > the CPU that they interrupt. If one of these clockevents were to > become a broadcast source we will run into a lot of trouble > because the broadcast source is enabled on the first CPU to go > into deep idle (if that CPU suffers from FEAT_C3_STOP) and that > could be a different CPU than what the clockevent is interrupting > (or even worse the CPU that the clockevent interrupts could be > offline). > > Theoretically it's possible to support per-cpu clockevents as the > broadcast source but so far we haven't needed this and supporting > it is rather complicated. Let's just deny the possibility for now > until this becomes a reality (let's hope it never does!). > > Reported-by: S?ren Brinkmann > Signed-off-by: Stephen Boyd Tested-by: S?ren Brinkmann This fixes the issue I reported when enabling the global timer on Zynq. The global timer is prevented from becoming the broadcast device and my system boots. Thanks, S?ren