From: Peter Hurley <peter@hurleysoftware.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
"Matwey V. Kornilov" <matwey@sai.msu.ru>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
jslaby@suse.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>
Subject: Re: [PATCH v3 2/5] tty: Introduce SER_RS485_SOFTWARE read-only flag for struct serial_rs485
Date: Thu, 12 Nov 2015 20:11:16 -0500 [thread overview]
Message-ID: <564538B4.20402@hurleysoftware.com> (raw)
In-Reply-To: <CAHp75Vdv-ycJfgA2xkjS2SrvL8N2vvrBMS-2d4ibBg-yvZying@mail.gmail.com>
On 11/12/2015 07:41 PM, Andy Shevchenko wrote:
> On Thu, Nov 12, 2015 at 10:22 PM, Peter Hurley <peter@hurleysoftware.com> wrote:
>> On 11/12/2015 02:57 PM, One Thousand Gnomes wrote:
>
>> An illustrative (kernel-space) example is the mess that is dmaengine_pause().
>> Some DMA implementations provide the means to stop and restart DMA without
>> losing data and some DMA implementations do not. Unfortunately, some
>> advertise they support dmaengine_pause() but only for lossy uses like audio.
>> Because the api hides this, the query interface for pause support is
>> useless.
>
> The DMA pause() call means only pause with possibility to resume.
> There is a resume() call as well. Any driver which treats pause() as a
> complete stop is buggy driver and should be fixed.
How about pause _without_ the possibility to resume?
https://groups.google.com/d/msg/linux.kernel/Abe0hfGcgsw/H0se55wC558J
next prev parent reply other threads:[~2015-11-13 1:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-12 14:33 [PATCH v3 0/5] tty: Introduce software RS485 direction control support Matwey V. Kornilov
2015-11-12 14:33 ` [PATCH v3 1/5] tty: Introduce UART_CAP_HW485 Matwey V. Kornilov
2015-11-12 14:33 ` [PATCH v3 2/5] tty: Introduce SER_RS485_SOFTWARE read-only flag for struct serial_rs485 Matwey V. Kornilov
2015-11-12 19:57 ` One Thousand Gnomes
2015-11-12 20:22 ` Peter Hurley
2015-11-13 0:41 ` Andy Shevchenko
2015-11-13 1:11 ` Peter Hurley [this message]
2015-11-13 1:26 ` Andy Shevchenko
2015-11-13 1:55 ` Peter Hurley
2015-11-14 15:25 ` One Thousand Gnomes
2015-11-16 19:18 ` Peter Hurley
2015-11-17 8:20 ` Matwey V. Kornilov
2015-11-18 18:33 ` Peter Hurley
2015-11-18 19:39 ` Matwey V. Kornilov
2015-11-18 19:49 ` Matwey V. Kornilov
2015-12-02 23:20 ` Peter Hurley
2015-12-03 5:50 ` Matwey V. Kornilov
2015-12-03 14:41 ` Peter Hurley
2015-12-03 17:29 ` Matwey V. Kornilov
2015-12-03 19:45 ` Peter Hurley
2015-12-04 17:50 ` Matwey V. Kornilov
2015-11-13 20:03 ` Matwey V. Kornilov
2015-11-12 14:33 ` [PATCH v3 3/5] tty: Implement default fallback serial8250_rs485_config Matwey V. Kornilov
2015-11-12 14:33 ` [PATCH v3 4/5] tty: Move serial8250_stop_rx in front of serial8250_start_tx Matwey V. Kornilov
2015-11-12 14:33 ` [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250 Matwey V. Kornilov
2015-11-12 14:48 ` Andy Shevchenko
2015-11-17 9:24 ` Uwe Kleine-König
2015-11-17 10:25 ` Matwey V. Kornilov
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