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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>, Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Esben Haabendal <esben@geanix.com>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Rengarajan S <rengarajan.s@microchip.com>,
	Serge Semin <fancer.lancer@gmail.com>,
	Lino Sanfilippo <l.sanfilippo@kunbus.com>
Subject: Re: [PATCH tty-next v3 2/6] serial: 8250: Use high-level write function for FIFO
Date: Fri, 25 Oct 2024 16:50:41 +0300	[thread overview]
Message-ID: <ZxuiMdrGcsuPp8OG@smile.fi.intel.com> (raw)
In-Reply-To: <20241025105728.602310-3-john.ogness@linutronix.de>

On Fri, Oct 25, 2024 at 01:03:24PM +0206, John Ogness wrote:
> Currently serial8250_console_fifo_write() directly writes into the
> UART_TX register, rather than using the high-level function
> serial8250_console_putchar(). This is because
> serial8250_console_putchar() waits for the holding register to
> become empty. That would defeat the purpose of the FIFO code.

You can slightly reformat the above to make it less shaky in terms
of the efficiency of a line capacity usage.

Currently serial8250_console_fifo_write() directly writes into
the UART_TX register, rather than using the high-level function
serial8250_console_putchar(). This is because
serial8250_console_putchar() waits for the holding register
to become empty. That would defeat the purpose of the FIFO code.

> Move the LSR_THRE waiting to a new function
> serial8250_console_wait_putchar() so that the FIFO code can use
> serial8250_console_putchar(). This will be particularly important
> for a follow-up commit, where output bytes are inspected to track
> newlines.

> This is only refactoring and has no functional change.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2024-10-25 13:51 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-25 10:57 [PATCH tty-next v3 0/6] convert 8250 to nbcon John Ogness
2024-10-25 10:57 ` [PATCH tty-next v3 1/6] serial: 8250: Adjust the timeout for FIFO mode John Ogness
2024-10-25 13:45   ` Andy Shevchenko
2024-10-25 13:51     ` Andy Shevchenko
2024-10-29 16:24     ` Wander Lairson Costa
2024-10-30  6:05   ` Jiri Slaby
2024-10-31  4:44     ` Maciej W. Rozycki
2024-10-31  8:49       ` John Ogness
2024-11-01  1:24         ` Maciej W. Rozycki
2024-11-01  8:21           ` Andy Shevchenko
2024-11-04  6:44         ` Jiri Slaby
2024-11-04  6:34       ` Jiri Slaby
2024-11-04 14:13         ` John Ogness
2024-12-02  6:12           ` Jiri Slaby
2024-12-02 16:41             ` John Ogness
2024-12-01  0:04         ` Maciej W. Rozycki
2024-10-25 10:57 ` [PATCH tty-next v3 2/6] serial: 8250: Use high-level write function for FIFO John Ogness
2024-10-25 13:50   ` Andy Shevchenko [this message]
2024-11-05 16:12   ` Petr Mladek
2024-10-25 10:57 ` [PATCH tty-next v3 3/6] serial: 8250: Split out rx stop/start code into helpers John Ogness
2024-10-25 13:55   ` Andy Shevchenko
2024-11-06 10:54   ` Petr Mladek
2024-10-25 10:57 ` [PATCH tty-next v3 4/6] serial: 8250: Specify console context for rs485_start/stop_tx John Ogness
2024-10-25 14:04   ` Andy Shevchenko
2024-10-25 14:25     ` John Ogness
2024-10-25 14:34       ` Andy Shevchenko
2024-10-30  6:13   ` Jiri Slaby
2024-10-31  9:13     ` John Ogness
2024-11-06 15:42   ` Petr Mladek
2024-11-29 17:45     ` John Ogness
2024-10-25 10:57 ` [PATCH tty-next v3 5/6] serial: 8250: Switch to nbcon console John Ogness
2024-10-25 14:22   ` Andy Shevchenko
2024-10-28 13:22     ` John Ogness
2024-11-07  9:48       ` Petr Mladek
2024-10-30  6:33   ` Jiri Slaby
2024-10-31  9:25     ` John Ogness
2024-10-25 10:57 ` [PATCH tty-next v3 6/6] serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()" John Ogness
2024-10-25 14:05   ` Andy Shevchenko
2024-10-25 13:58 ` [PATCH tty-next v3 0/6] convert 8250 to nbcon Andy Shevchenko

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