linux-kernel - Re: [PATCH/RFC] serial_core: Fix pm imbalance on unbind

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Message-ID: <CAMuHMdVmrEoRkqUB=3mBRNrPEJiR701YUmr8C7HX1O6UxT_NUg@mail.gmail.com>
Date:	Thu, 20 Mar 2014 11:23:00 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>
Cc:	linux-serial@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux-sh list <linux-sh@...r.kernel.org>,
	Geert Uytterhoeven <geert+renesas@...ux-m68k.org>
Subject: Re: [PATCH/RFC] serial_core: Fix pm imbalance on unbind

Hi Greg,

On Mon, Mar 10, 2014 at 8:54 PM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> From: Geert Uytterhoeven <geert+renesas@...ux-m68k.org>
>
> When a serial port is closed, uart_close() takes care of shutting down the
> hardware, and powering it down.
>
> When a serial port is unbound while in use, uart_close() bypasses all of
> this, as this is supposed to be done through uart_hangup() (invoked via
> tty_vhangup() in uart_remove_one_port()).
>
> However, uart_hangup() does not set the hardware's power state, leaving it
> powered up.  This may also lead to unbounded nesting counts in clock and
> power management, depending on their internal implementation.
>
> Make sure to power down the port in uart_hangup(), except when the port is
> used as a serial console. For serial consoles, this must be postponed until
> after their deregistration in uart_remove_one_port() (symmetry with
> registration in uart_configure_port(), invoked from uart_add_one_port()).
>
> After this, the module clock used by the sh-sci driver is disabled on
> unbind while the serial port is in use.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...ux-m68k.org>

I noticed you have applied all serial patches I've sent, except for this one.
Is there any specific reason you skipped this one?

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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