From mboxrd@z Thu Jan 1 00:00:00 1970 From: Govindraj Subject: Re: [PATCH v2 05/12] OMAP: Serial: Hold console lock for console usage. Date: Wed, 4 May 2011 15:49:48 +0530 Message-ID: References: <1304080796-625-1-git-send-email-govindraj.raja@ti.com> <1304080796-625-6-git-send-email-govindraj.raja@ti.com> <20110504100232.GA2092@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20110504100232.GA2092@atomide.com> Sender: linux-serial-owner@vger.kernel.org To: Tony Lindgren Cc: "Govindraj.R" , linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Benoit Cousson , Kevin Hilman , Paul Walmsley , Rajendra Nayak List-Id: linux-omap@vger.kernel.org On Wed, May 4, 2011 at 3:32 PM, Tony Lindgren wrote: > * Govindraj.R [110429 05:39]: >> >> Also during bootup console_lock is not available. >> =A0 =A0 =A0 =A0--> uart_add_one_port >> =A0 =A0 =A0 =A0 =A0--> console_register >> =A0 =A0 =A0 =A0 =A0 =A0 =A0--> console_lock >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 --> console_unlock >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0--> call_console_drivers (her= e yet console_lock is not released) >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 --> uart_console_wri= te >> >> Hence convert prints from omap_device_enable/disable to pr_debug. > > This sounds like a hack considering we have things working with > pr_debug currently. The reason it works currently is because we are aquiring console lock in omap_serial_init since with the patch series cleanup and things are moving to driver I see this issue. The issue is due to recursive prints because of get_sync/put_sync printing active/deactivate latency from omap_device layer. During printk -> uart_console_write --> we do get_sync and if clock is cut and omap_device_enable gets called and omap_device_enable trying to pr_warn activate latency. Here we end up in recursive lock up from printk. -- Thanks, Govindraj.R > > Tony > -- > To unsubscribe from this list: send the line "unsubscribe linux-seria= l" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =A0http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html