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References: <20240425070936.547100-1-claudiu.beznea.uj@bp.renesas.com>
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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 25 Apr 2024 09:48:39 +0200
Message-ID: <CAMuHMdX_uojDmx3pH--KsBcae=1VmcNupedGBwovVQcU+z14sg@mail.gmail.com>
Subject: Re: [RFT PATCH v2] serial: core: Call device_set_awake_path() for
 console port
To: Claudiu <claudiu.beznea@tuxon.dev>
Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org, tony@atomide.com, 
	andriy.shevchenko@linux.intel.com, l.sanfilippo@kunbus.com, 
	tglx@linutronix.de, geert+renesas@glider.be, ulf.hansson@linaro.org, 
	peng.fan@nxp.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, 
	linux-pm@vger.kernel.org, Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
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On Thu, Apr 25, 2024 at 9:09=E2=80=AFAM Claudiu <claudiu.beznea@tuxon.dev> =
wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> In case the UART port is used as a console, no_console_suspend is
> available in bootargs and UART port is part of a software-controlled powe=
r
> domain we need to call device_set_awake_path(). This lets the power
> domain core code know that this domain should not be powered off
> during system suspend. Otherwise, the UART port power domain is turned of=
f,
> nothing is printed while suspending and the suspend/resume process is
> blocked. This was detected on the Renesas RZ/G3S SoC while adding support
> for power domains.
>
> Based on code investigation, this issue is present on other SoCs (e.g.,
> Renesas R-Mobile A1 [1], IMX8QXP [2]) and different SoCs have particular
> implementation to handle it. Due to this the patch added the call of
> device_set_awake_path() in uart_suspend_port() instead of having it in
> the platform specific UART driver.
>
> [1] https://elixir.bootlin.com/linux/v6.9-rc5/source/drivers/pmdomain/ren=
esas/rmobile-sysc.c#L116
> [2] https://elixir.bootlin.com/linux/v6.9-rc5/source/drivers/pmdomain/imx=
/scu-pd.c#L357
>
> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
> Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Works fine on R-Mobile APE6 with console suspend support removed from
rmobile-sysc.c
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds