From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: OMAP34xx Date: Tue, 07 Feb 2012 14:36:06 -0800 Message-ID: <87lioegtk9.fsf@ti.com> References: <20120204185453.GB17309@n2100.arm.linux.org.uk> <20120204190109.GL20333@atomide.com> <20120204203453.GD17309@n2100.arm.linux.org.uk> <20120205012556.GG1426@atomide.com> <20120205125904.GB11372@n2100.arm.linux.org.uk> <20120205172925.GS20333@atomide.com> <20120205175809.GF17309@n2100.arm.linux.org.uk> <20120205182910.GK1426@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from na3sys009aog117.obsmtp.com ([74.125.149.242]:41534 "EHLO na3sys009aog117.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756699Ab2BGWgK (ORCPT ); Tue, 7 Feb 2012 17:36:10 -0500 Received: by mail-pz0-f42.google.com with SMTP id g27so9997352dan.1 for ; Tue, 07 Feb 2012 14:36:09 -0800 (PST) In-Reply-To: <20120205182910.GK1426@atomide.com> (Tony Lindgren's message of "Sun, 5 Feb 2012 10:29:10 -0800") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tony Lindgren Cc: Russell King - ARM Linux , linux-omap@vger.kernel.org, Arnd Bergmann , Olof Johansson Tony Lindgren writes: [...] >> > > --- a/arch/arm/mach-omap2/pm34xx.c >> > > +++ b/arch/arm/mach-omap2/pm34xx.c >> > > @@ -420,7 +420,7 @@ static void omap3_pm_idle(void) >> > > { >> > > local_fiq_disable(); >> > > >> > > - if (omap_irq_pending()) >> > > + if (omap_irq_pending() || 1) >> > > goto out; >> > > >> > > trace_power_start(POWER_CSTATE, 1, smp_processor_id()); >> > >> > This does not look right to me. I thought reverting of the serial >> > patches should have already solved the issue you're seeing with >> > slow serial port? >> > >> > Those are the reverting commits drivers/tty/serial/serial-omap.c: >> > >> > 8a74e9ffd97dc9de063de8c02ae32db79dd60436 (Revert "tty: serial: OMAP: ensure >> > FIFO levels are set correctly in non-DMA mode") >> > >> > af681cad3f79ad8f7bd6cb170b70990aeef74233 (Revert "tty: serial: OMAP: transmit >> > FIFO threshold interrupts don't wake the chip") >> >> These commits have absolutely nothing to do with it. I pointed out the >> bad commit in one of my emails: >> >> commit 2fd149645eb46d26130d7070c6de037dddf34880 >> Author: Govindraj.R >> Date: Wed Nov 9 17:41:21 2011 +0530 >> >> ARM: OMAP2+: UART: Remove omap_uart_can_sleep and add pm_qos >> >> Omap_uart_can_sleep function blocks system wide low power state until >> uart is active remove this func and add qos requests to prevent >> MPU from transitioning. >> >> Keep qos request to default value which will allow MPU to transition >> and while uart baud rate is available calculate the latency value >> from the baudrate and use the same to hold constraint while uart clocks >> are enabled, and if uart is auto-idled the constraint is updated with >> default constraint value allowing MPU to transition. >> >> Qos requests are blocking notifier calls so put these requests to >> work queue, also the driver uses irq_safe version of runtime API's >> and callbacks can be called in interrupt disabled context. >> So to avoid warn on slow path warning while using qos update >> API's from runtime callbacks use the qos_work_queue. >> >> During bootup the runtime_resume call backs might not be called and runtime >> callback gets called only after uart is idled by setting the autosuspend >> timeout. So qos_request from runtime resume callback might not activated during >> boot if uart baudrate is calculated during bootup for console uart, so schedule >> the qos_work queue once we calc_latency while configuring the uart port. >> >> Flush and complete any pending qos jobs in work queue while suspending. >> >> Signed-off-by: Govindraj.R >> Acked-by: Greg Kroah-Hartman (for drivers/tty changes) >> Signed-off-by: Kevin Hilman >> >> Basically, it looks like the OMAP 3 UART is not delivering transmit IRQs >> while in some of the deeper low power modes. >> >> I tried reverting the rest of the patches between this one and HEAD for >> omap-serial.c, but they have no effect what so ever on this bug. As I >> said in one of my emails in this thread, the above commit can't be >> trivially reverted because some other stuff that the code relied upon >> has vanished. >> >> So, the above along with the other part in arch/arm/mach-omap2/cpuidle34xx.c >> is the smallest 'fix' I could find if resolving the regression. > > OK, thanks, that should be enough info for let Kevin take a look at this. This one is indeed strange. I have not seen this on the 34xx devices I'm using (3430/n900, 3530/Overo, 3630/Zoom3). Just to confirm. I assume you are using v3.3-rc2 (or later Linus master) which has a few fixes for this driver already. Also, is this happening on your LDP. Which ES revision does your 3430 have? Kevin