From: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
<linux-arm-kernel@lists.infradead.org>,
Michal Simek <michal.simek@xilinx.com>,
<linux-serial@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATH RESEND v2 03/10] tty: xuartps: Always enable transmitter in start_tx
Date: Fri, 20 Nov 2015 09:05:26 -0800 [thread overview]
Message-ID: <20151120170525.GW32017@xsjsorenbubuntu> (raw)
In-Reply-To: <564F0E75.5020100@hurleysoftware.com>
On Fri, 2015-11-20 at 07:13AM -0500, Peter Hurley wrote:
>
>
> On 11/19/2015 03:02 PM, Soren Brinkmann wrote:
> > start_tx must start transmitting characters. Regardless of the state of
> > the circular buffer, always enable the transmitter hardware.
>
> Why?
>
> Does cdns_uart_stop_tx() actually stop the transmitter so that
> data remains in the transmitter?
Fixing up the patch, I looked at this one. It might actually do that.
Without having changed anything. The doc says: "The driver should
stop transmitting characters as soon as possible.". And the
implementation is really not draining any FIFO, but just disabling the
transmitter. I take your question as that this might not be this way?
Should stop_tx drain the FIFO first?
Thanks,
Sören
next prev parent reply other threads:[~2015-11-20 17:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-19 20:02 [PATH RESEND v2 00/10] tty: xuartps: Fix lock ups Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 01/10] tty: xuartps: Beautify read-modify writes Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 02/10] tty: xuartps: Use spinlock to serialize HW access Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 03/10] tty: xuartps: Always enable transmitter in start_tx Soren Brinkmann
2015-11-20 12:13 ` Peter Hurley
2015-11-20 15:28 ` Sören Brinkmann
2015-11-20 16:30 ` Peter Hurley
2015-11-20 16:58 ` Sören Brinkmann
2015-11-20 17:16 ` Peter Hurley
2015-11-20 17:29 ` Sören Brinkmann
2015-11-23 7:05 ` Michal Simek
2015-11-23 20:00 ` Peter Hurley
2015-11-24 7:26 ` Michal Simek
2015-11-20 17:05 ` Sören Brinkmann [this message]
2015-11-20 17:12 ` Peter Hurley
2015-11-19 20:02 ` [PATH RESEND v2 04/10] tty: xuartps: Clear interrupt status register in shutdown Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 05/10] tty: xuartps: Improve startup function Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 06/10] tty: xuartps: Keep lock for whole ISR Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 07/10] tty: xuartps: Acquire port lock for shutdown Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 08/10] tty: xuartps: Move RX path into helper function Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled Soren Brinkmann
2015-11-19 20:02 ` [PATH RESEND v2 10/10] tty: xuartps: Cleanup: Reformat if-else Soren Brinkmann
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