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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Esben Haabendal <esben@geanix.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Kevin Hilman <khilman@baylibre.com>,
	Markus Schneider-Pargmann <msp@baylibre.com>,
	Udit Kumar <u-kumar1@ti.com>,
	Griffin Kroah-Hartman <griffin@kroah.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Rengarajan S <rengarajan.s@microchip.com>,
	Lino Sanfilippo <l.sanfilippo@kunbus.com>,
	Niklas Schnelle <schnelle@linux.ibm.com>,
	Serge Semin <fancer.lancer@gmail.com>,
	Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH tty-next v1 2/4] serial: 8250: Do not set UART_LSR_THRE in @read_status_mask
Date: Mon, 16 Dec 2024 22:36:56 +0200	[thread overview]
Message-ID: <Z2CPaOehREibSzVD@smile.fi.intel.com> (raw)
In-Reply-To: <20241216171244.12783-3-john.ogness@linutronix.de>

On Mon, Dec 16, 2024 at 06:18:42PM +0106, John Ogness wrote:
> Since Linux 2.1.8 @read_status_mask is no longer used as a
> general control of which bits are used from the LSR register.

The curious ones may add history/history.git to their repo and run
`git show 2.1.8 -- drivers/char/serial.c` to see how it was done.

> Instead it has become an additional mask applied to
> @ignore_status_mask. Since UART_LSR_THRE is never set for
> @ignore_status_mask, it serves no purpose to set it for
> @read_status_mask. In fact, it propagates the misconception
> that @read_status_mask can be used as a general mask for LSR
> bits.

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2024-12-16 20:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-16 17:12 [PATCH tty-next v1 0/4] serial: 8250: Fix LSR masking John Ogness
2024-12-16 17:12 ` [PATCH tty-next v1 1/4] serial: 8250: Use @ier bits to determine if Rx is stopped John Ogness
2024-12-16 20:31   ` Andy Shevchenko
2024-12-16 20:43     ` Andy Shevchenko
2024-12-20 11:50       ` John Ogness
2024-12-24 15:59         ` Andy Shevchenko
2024-12-16 17:12 ` [PATCH tty-next v1 2/4] serial: 8250: Do not set UART_LSR_THRE in @read_status_mask John Ogness
2024-12-16 20:36   ` Andy Shevchenko [this message]
2024-12-16 17:12 ` [PATCH tty-next v1 3/4] serial: 8250: Never adjust UART_LSR_DR " John Ogness
2024-12-16 17:12 ` [PATCH tty-next v1 4/4] serial: 8250: Explain the role of @read_status_mask John Ogness

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