From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756394Ab0IGKyo (ORCPT ); Tue, 7 Sep 2010 06:54:44 -0400 Received: from out1.smtp.messagingengine.com ([66.111.4.25]:36548 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755532Ab0IGKyj (ORCPT ); Tue, 7 Sep 2010 06:54:39 -0400 X-Sasl-enc: 9rUGnomnvbD4t9gEINOdEO6Fmmiio6CG2JoqxrAmG1ck 1283856878 Message-ID: <4C861A09.5020203@ladisch.de> Date: Tue, 07 Sep 2010 12:55:05 +0200 From: Clemens Ladisch User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Jaswinder Singh Rajput CC: the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: Hungry for hardware timers References: <4C85F0E3.2050908@ladisch.de> <4C860043.9000501@ladisch.de> In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jaswinder Singh Rajput wrote: > If I access /dev/hpet by hpet_example it shows that it is using HPET > T0 as hi_hpet is 0 : > > #./hpet_example info /dev/hpet > -hpet: executing info > hpet_info: hi_irqfreq 0x0 hi_flags 0x0 hi_hpet 0 hi_timer 2 This means HPET block 0, timer 2. In practice, there is no machine with more than one HPET block, so hi_hpet is rather useless. > What will be IRQ # for T2. Just check while hpet_example is running ... > As per dmesg([ 0.325958] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0) > so IRQs are like this : > HPET T0 : 2 > HPET T1 : 8 > HPET T2 : 0 "0" means that the BIOS did not initialize it. In this case, the driver will initializes it when accessed, with the first supported IRQ above 15. On your HPET's T2, this is IRQ 20. Regards, Clemens