Re: [PATCH v3 2/5] tty: Introduce SER_RS485_SOFTWARE read-only flag for struct serial_rs485

Andy Shevchenko
2015-11-13T00:41:58Z

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.

--
With Best Regards,
Andy Shevchenko