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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Phil Elwell <phil@raspberrypi.com>
Cc: Wander Lairson Costa <wander@redhat.com>,
	Johan Hovold <johan@kernel.org>,
	"Maciej W. Rozycki" <macro@orcam.me.uk>,
	Lukas Wunner <lukas@wunner.de>,
	Florian Fainelli <f.fainelli@gmail.com>,
	linux-serial@vger.kernel.org,
	linux-rpi-kernel@lists.infradead.org
Subject: Re: [PATCH] serial: 8250: Fix ...console_fifo_write on BCM283x
Date: Wed, 26 Jan 2022 15:21:29 +0100	[thread overview]
Message-ID: <YfFY6Rnor85CE9yH@kroah.com> (raw)
In-Reply-To: <20220126141124.4086065-1-phil@raspberrypi.com>

On Wed, Jan 26, 2022 at 02:11:24PM +0000, Phil Elwell wrote:
> The mini-UART on BCM283x is doubly crippled - it has 8-byte FIFOs and
> the THRE bit indicates that the TX FIFO is not-full rather than empty.
> 
> The optimisation to enable the use of the FIFO assumes that it is safe
> to write fifosize bytes whenever THRE is set, but the BCM283x quirk
> (indicated by the presence of UART_CAP_MINI) makes it necessary to
> check the FIFO state after each byte.
> 
> See: https://github.com/raspberrypi/linux/issues/4849
> 
> Fixes: 5021d709b31b ("tty: serial: Use fifo in 8250 console driver")

I have just reverted this commit, it's broken for many platforms now,
not just yours.

So there shouldn't be a need for this change now, right?

thanks,

greg k-h

  reply	other threads:[~2022-01-26 14:21 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-26 14:11 [PATCH] serial: 8250: Fix ...console_fifo_write on BCM283x Phil Elwell
2022-01-26 14:21 ` Greg Kroah-Hartman [this message]
2022-01-26 14:27   ` Phil Elwell

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