From: soren.brinkmann@xilinx.com (Sören Brinkmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATH RESEND v2 03/10] tty: xuartps: Always enable transmitter in start_tx
Date: Fri, 20 Nov 2015 07:28:49 -0800 [thread overview]
Message-ID: <20151120152849.GU32017@xsjsorenbubuntu> (raw)
In-Reply-To: <564F0E75.5020100@hurleysoftware.com>
Hi Peter,
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?
Well, I saw my system freezing and the cause seemed to be that the UART
receiver and/or transmitters were disabled while the system was trying
to print. Hence, I started questioning all locations touching the
transmitter/receiver enable. I read the docs in
https://www.kernel.org/doc/Documentation/serial/driver, which simply
says "Start transmitting characters." for start_tx(). Hence, I thought,
this function is probably supposed to just do that and start the
transmitter. I'll test whether this patch can be dropped.
Thanks,
S?ren
next prev parent reply other threads:[~2015-11-20 15:28 UTC|newest]
Thread overview: 23+ 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
2015-11-19 23:15 ` Peter Hurley
2015-11-20 12:13 ` Peter Hurley
2015-11-20 15:28 ` Sören Brinkmann [this message]
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
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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