From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Jiri Slaby" <jirislaby@kernel.org>,
"Tony Lindgren" <tony@atomide.com>,
"Maximilian Luz" <luzmaximilian@gmail.com>,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
"Andy Shevchenko" <andy@kernel.org>,
platform-driver-x86@vger.kernel.org,
linux-serial@vger.kernel.org,
"Weifeng Liu" <weifeng.liu.z@gmail.com>,
"Tony Lindgren" <tony.lindgren@linux.intel.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH] serial: Clear UPF_DEAD before calling tty_port_register_device_attr_serdev()
Date: Fri, 10 May 2024 16:43:47 +0300 [thread overview]
Message-ID: <CAHp75VfdZYVSbNfAQ5OzX632f-oGeU08-pHPWb9tf34Q1QU_RA@mail.gmail.com> (raw)
In-Reply-To: <20240509141549.63704-1-hdegoede@redhat.com>
On Thu, May 9, 2024 at 5:16 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> If a serdev_device_driver is already loaded for a serdev_tty_port when it
> gets registered by tty_port_register_device_attr_serdev() then that
> driver's probe() method will be called immediately.
>
> The serdev_device_driver's probe() method should then be able to call
> serdev_device_open() successfully, but because UPF_DEAD is still dead
> serdev_device_open() will fail with -ENXIO in this scenario:
>
> serdev_device_open()
> ctrl->ops->open() /* this callback being ttyport_open() */
> tty->ops->open() /* this callback being uart_open() */
> tty_port_open()
> port->ops->activate() /* this callback being uart_port_activate() */
> Find bit UPF_DEAD is set in uport->flags and fail with errno -ENXIO.
>
> Fix this be clearing UPF_DEAD before tty_port_register_device_attr_serdev()
> note this only moves up the UPD_DEAD clearing a small bit, before:
>
> tty_port_register_device_attr_serdev();
> mutex_unlock(&tty_port.mutex);
> uart_port.flags &= ~UPF_DEAD;
> mutex_unlock(&port_mutex);
>
> after:
>
> uart_port.flags &= ~UPF_DEAD;
> tty_port_register_device_attr_serdev();
> mutex_unlock(&tty_port.mutex);
> mutex_unlock(&port_mutex);
I guess I have given the tag, anyway since Tony OK with this, no more questions:
Reviewed-by: Andy Shevchenko <andy@kernel.org>
--
With Best Regards,
Andy Shevchenko
prev parent reply other threads:[~2024-05-10 13:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 14:15 [PATCH] serial: Clear UPF_DEAD before calling tty_port_register_device_attr_serdev() Hans de Goede
2024-05-10 13:01 ` Tony Lindgren
2024-05-10 13:43 ` Andy Shevchenko [this message]
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