Re: [PATCH] ARM: OMAP2: UART: fix console UART mismatched runtime PM status

[Felipe Balbi <balbi@ti.com>]

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Hi,

On Mon, Oct 15, 2012 at 04:49:58PM -0700, Kevin Hilman wrote:
> From: Kevin Hilman <khilman@ti.com>
> 
> The runtime PM framework assumes that the hardware state of devices
> when initialized is disabled.  For all omap_devices, we idle/disable
> device by default.  However, the console uart uses a "no idle" option
> during omap_device init in order to allow earlyprintk usage to work
> seamlessly during boot.
> 
> Because the hardware is left partially enabled after init (whatever
> the bootloader settings were), the omap_device should later be fully
> initialized (including mux) and the runtime PM framework should be
> told that the device is active, and not disabled so that the hardware
> state is in sync with runtime PM state.
> 
> To fix, after the device has been created/registered, call
> omap_device_enable() to finialize init and use pm_runtime_set_active()
> to tell the runtime PM core the device is enabled.
> 
> Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
> 3730/Beagle-xM, 4460/PandaES.
> 
> Reported-by: Paul Walmsley <paul@pwsan.com>
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Cc: Felipe Balbi <balbi@ti.com>
> Cc: Sourav Poddar <sourav.poddar@ti.com>
> Signed-off-by: Kevin Hilman <khilman@ti.com>
> ---
> Applies against v3.7-rc1.
> Fix targetted for v3.7.
> 
> I'm still not entirely sure why this has worked up to now on OMAP3/4
> but not on OMAP2.  Even so, this fix is needed for all platforms to
> ensure matching hardware state and runtime PM state.
> 
>  arch/arm/mach-omap2/serial.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> index 0405c81..37b5dbe 100644
> --- a/arch/arm/mach-omap2/serial.c
> +++ b/arch/arm/mach-omap2/serial.c
> @@ -327,6 +327,11 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
>  	if ((console_uart_id == bdata->id) && no_console_suspend)
>  		omap_device_disable_idle_on_suspend(pdev);
>  
> +	if (console_uart_id == bdata->id) {
> +		omap_device_enable(pdev);
> +		pm_runtime_set_active(&pdev->dev);
> +	}
> +
>  	oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
>  
>  	oh->dev_attr = uart;

looks good to me. Even took care of doing that only for the console
UART.

Reviewed-by: Felipe Balbi <balbi@ti.com>

sorry for the issues caused.

-- 
balbi

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