From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: AM335x: Beaglebone stops to boot with current git kernel Date: Tue, 04 Dec 2012 13:39:44 -0800 Message-ID: <87pq2pa44f.fsf@deeprootsystems.com> References: <20121121183809.GZ18567@atomide.com> <50ADBB5B.7090401@ti.com> <79CD15C6BA57404B839C016229A409A83EB7F222@DBDE01.ent.ti.com> <79CD15C6BA57404B839C016229A409A83EB7FB16@DBDE01.ent.ti.com> <87mwxvathj.fsf@deeprootsystems.com> <79CD15C6BA57404B839C016229A409A83EBA3979@DBDE01.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:45906 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752157Ab2LDVjd (ORCPT ); Tue, 4 Dec 2012 16:39:33 -0500 Received: by mail-pa0-f46.google.com with SMTP id bh2so3053265pad.19 for ; Tue, 04 Dec 2012 13:39:33 -0800 (PST) In-Reply-To: <79CD15C6BA57404B839C016229A409A83EBA3979@DBDE01.ent.ti.com> (Vaibhav Hiremath's message of "Tue, 4 Dec 2012 04:01:30 +0000") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Hiremath, Vaibhav" Cc: Joel A Fernandes , Igor Mazanov , Tony Lindgren , Jean Pihet , "Menon, Nishanth" , "linux-omap@vger.kernel.org" "Hiremath, Vaibhav" writes: > On Mon, Dec 03, 2012 at 23:49:36, Kevin Hilman wrote: >> "Hiremath, Vaibhav" writes: >> >> >> >>> +static struct omap_hwmod am33xx_debugss_hwmod = { >> >> >>> + .name = "debugss", >> >> >>> + .class = &am33xx_debugss_hwmod_class, >> >> >>> + .clkdm_name = "l3_aon_clkdm", >> >> >>> + .main_clk = "debugss_ick", >> >> >>> + .flags = (HWMOD_INIT_NO_IDLE | HWMOD_INIT_NO_RESET), >> >> >> >> Setting these flags would still leave the problem where JTAG clocks >> >> are on when its not required no? In that case, what is the advantage >> >> of this patch? >> >> >> > >> > I missed to wrap it around #ifdef CONFIG_DEBUG_KERNEL. I will submit the >> > formal patch shortly. >> >> IMO, this should not be handled in the data at all (neither clock nor >> hwmod), and should be handled at runtime/boot-time, not compile time. >> > > Wouldn't that become another interface/control for debug? We already have > various (standard) debug kernel parameters available. > > But I see your point, compile-time option will force users to rebuild kernel > just in order to disable JTAG/Debug clock. > >> The solution to this is to rather to have a small bit of code that >> requests the debugss clocks that are needed for JTAG debug, so the >> kernel knows they are in use. >> >> That code could then be enabled at boot time via command-line or DT >> option. >> > > In case of command-line, something like below??? > > static int __init omap2_debug_clk_enable(char *str) > { > if (!str) > return 0; > > if (!strcmp(str, "debug")) > > > return 0; > } > early_param("debug", omap2_debug_clk_enable); Yes, that's the idea I had in mind. Though you don't want to override "debug" here. The debug option is specifically about default log levels for the console and isn't really related to clocks. Kevin