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Message-ID: <51713259.7000205@ti.com> Date: Fri, 19 Apr 2013 15:02:33 +0300 From: Grygorii Strashko <grygorii.strashko@...com> To: Sourav Poddar <sourav.poddar@...com> CC: Kevin Hilman <khilman@...aro.org>, <gregkh@...uxfoundation.org>, <tony@...mide.com>, <rmk+kernel@....linux.org.uk>, <linux-serial@...r.kernel.org>, <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Santosh Shilimkar <santosh.shilimkar@...com>, Felipe Balbi <balbi@...com>, Rajendra nayak <rnayak@...com> Subject: Re: [PATCH 0/6] Serial Omap fixes and cleanups On 04/18/2013 10:17 PM, Sourav Poddar wrote: > Hi Kevin, > On Thursday 18 April 2013 11:53 PM, Kevin Hilman wrote: >> Hi Sourav, >> >> Sourav Poddar<sourav.poddar@...com> writes: >> >>> Hi, >>> >>> This patch series contains fixes and cleanups around the issue that >>> the console UART should not idled on suspend while using >>> "no_console_suspend" >>> in bootargs. >>> >> The direction of the series is right, thanks for the updated approach. >> I had a comple minor comments on specific patches, but the ordering of >> the series needs a little tweaking. It should be >> >> - core/driver changes [current 1-3/6 are ok] >> - remove usage from mach-omap2/serial.c (currently part of 4/6) >> - remove am33x DT usage (current 5/6 is ok) >> - remove entirely from omap_device (omap_device part of 4/6 and 6/6 >> should be combined) >> > Thanks a lot for your review and comments. > I have replied to your comments on the respective patches. > Will take care of the "ordering" which you mentioned above > in the next version. > > Thanks > Sourav Hi Sourav I'd like to clarify some points regarding this series: 1) I'm not sure that removing OMAP_DEVICE_NO_IDLE_ON_SUSPEND is fine. FYI - review.omapzoom.org/#/q/status:open,n,zI9e21bf4432a537a4ccb217cf9c425b0e4e499ce8 "ASoC: omap-abe: Allow no idle on suspend" The above "voice call" use case allows Audio playback while system is in "suspend" state. In addition HSI and SmartReflex may need to be active after suspend_noirq stage. By removing this flag such functionality will be broken (in case of porting it on newest Kernel or MainLine). So, How it can be handled without OMAP_DEVICE_NO_IDLE_ON_SUSPEND? 2) Runtime PM vs System suspend - The commit 88d26136a "PM: Prevent runtime suspend during system resume" block pm_runtime_put_xx() while suspending/resuming, so if your UART will became active (at least one call to pm_runtime_get_xx()) while system is suspending it will stay active until suspend_noirq stage. - At suspend_noirq stage OMAP device framework will finally (brutally) disable it to reach system suspend state (in _od_suspend_noirq). - At resume_noirq stage OMAP device framework will re-enable device if it was disabled in _od_suspend_noirq() to keep device state and Runtime PM in sync. - In addition, the commit 9f6d8f6 "PM: Move disabling/enabling runtime PM to late suspend/early resume" will disable Runtime PM at suspend_late and enable it resume_early stages. As, result: - serial_omap_prepare()/serial_omap_complete() not needed - usually console is active. Or you may call pm_runtime_get_xxx() in serial_omap_prepare() to be sure (that's all) - removing OMAP_DEVICE_NO_IDLE_ON_SUSPEND will not help, because to handle your use case omap_device_idle() need to be removed from od_suspend_noirq(). !! Which, in turn, will kill OMAP suspend !! (see Kevin's comments) Unfortunately, I see no way to avoid usage OMAP_DEVICE_NO_IDLE_ON_SUSPEND with the current OMAP device framework. Regards, -grygorii >> Kevin >> >>> The approach thought of is to modify the serial core/serial driver >>> to bypass >>> runtime PM if the UART in contention is a console and we are using >>> "no_console_suspend" >>> in our bootargs. >>> >>> While fixing the above issue, there are other cleanups also done as >>> part of >>> this series which are no longer required. This cleanups mainly >>> include getting >>> rid of using "omap_device_disable_idle_on_suspend" api for both dt >>> and non dt case >>> as the serial driver will be self sufficient to handle the >>> "no_idle_on_suspend" issue. >>> Serial was the only one making use of >>> "omap_device_disable_idle_on_suspend" >>> >>> Test info (except drivers: serial: mpc52xx_uart: Remove >>> "uart_console" defintion): >>> Omap4430sdp: >>> - Tested wakeup from UART after suspend for dt and non dt case. >>> Omap5430evm: >>> - Tested wakeup from UART after suspend for dt case. >>> >>> >>> There were discussions about how to handle "no_idle_on_suspend" >>> issue and all the >>> discussions are as follows: >>> [v3]: https://lkml.org/lkml/2013/4/5/239 >>> [v2]: https://lkml.org/lkml/2013/4/2/350 >>> [v1]: https://lkml.org/lkml/2013/3/18/199 >>> https://lkml.org/lkml/2013/3/18/295 >>> Due to the amount of change in approach and other cleanups coming >>> around it, I am posting >>> this as a new series. >>> >>> This patches are based on 3.9-rc3 custom tree which has >>> Santosh Shilimkar serial patch[1] >>> [1]: http://permalink.gmane.org/gmane.linux.ports.arm.omap/95828 >>> >>> Cc: Santosh Shilimkar<santosh.shilimkar@...com> >>> Cc: Felipe Balbi<balbi@...com> >>> Cc: Rajendra nayak<rnayak@...com> >>> >>> Sourav Poddar (6): >>> drivers: tty: serial: Move "uart_console" def to core header file. >>> drivers: serial: mpc52xx_uart: Remove "uart_console" defintion >>> driver: serial: omap: add prepare/complete callback for >>> "no_console_suspend" case >>> arm: mach-omap2: remove "OMAP_DEVICE_NO_IDLE_ON_SUSPEND" check >>> arm: dts: am33xx: Remove "ti,no_idle_on_suspend" property. >>> arm: mach-omap2: Remove "no_console_suspend" >>> >>> arch/arm/boot/dts/am33xx.dtsi | 1 - >>> arch/arm/mach-omap2/omap_device.c | 10 +--------- >>> arch/arm/mach-omap2/serial.c | 7 ------- >>> drivers/tty/serial/mpc52xx_uart.c | 10 ---------- >>> drivers/tty/serial/omap-serial.c | 20 ++++++++++++++++++++ >>> drivers/tty/serial/serial_core.c | 6 ------ >>> include/linux/serial_core.h | 6 ++++++ >>> 7 files changed, 27 insertions(+), 33 deletions(-) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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