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Date:   Wed, 13 Jun 2018 17:59:38 +0100
From:   Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To:     Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc:     matwey.kornilov@gmail.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>,
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        Joel Stanley <joel@jms.id.au>,
        Sean Wang <sean.wang@mediatek.com>,
        linux-serial@vger.kernel.org (open list:SERIAL DRIVERS),
        linux-kernel@vger.kernel.org (open list)
Subject: Re: [PATCH 3/4] serial: 8250: Handle case port doesn't have TEMT
 interrupt using em485.
Message-ID: <20180613175915.279d03e2@alans-desktop>
In-Reply-To: <20180606095156.72628-2-giulio.benetti@micronovasrl.com>
References: <CAJs94EZqdQAQG+inWvj89FCQtv06LxhY_J4YgNmK8mtvgDTchQ@mail.gmail.com>
        <20180606095156.72628-1-giulio.benetti@micronovasrl.com>
        <20180606095156.72628-2-giulio.benetti@micronovasrl.com>
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> +		} else {
> +			while ((lsr & BOTH_EMPTY) != BOTH_EMPTY) {
> +				lsr = serial_in(p, UART_LSR);
> +				cpu_relax();
> +			}
> +		}

This still needs a timeout in case some kind of hardware flow control line
is asserted and therefore the byte is staying put.

Alan