Re: [RFC RESEND] serial: 8250: fix regression in 8250 uart driver

[Andy Shevchenko]

On Sat, 2016-07-02 at 13:53 +0200, Thorsten Leemhuis wrote:
> On 14.06.2016 18:00, Andy Shevchenko wrote:
> > On Tue, 2016-06-14 at 10:27 -0500, dinh.linux@xxxxxxxxxxxxx wrote:
> > > > On Mon, 2016-06-13 at 21:59 -0500, Dinh Nguyen wrote:
> > > > I suppose this one, i.e. commit dd4e91d538b3 ("dmaengine: slave
> > > > means at
> > > > least one of DMA_SLAVE, DMA_CYCLIC"), solves the issue.
> > > Hmm...that commit didn't seem to fix my issue.
> > [â]
> > > Does this mean that the 8250_dw.c driver can no longer use DMA?
> > 
> > It means that previously the use of DMA engine whatever was used is
> > not
> > correct in your case. There is no issues in UART driver, the issue
> > is in
> > DMA controller driver.
> > 
> > I'm working on a quirk that will allow user to enforce PIO mode for
> > Rx/Tx or both. In that case if DMA controller can't be fixed you
> > still
> > might use DMA for Tx.
> 
> What's the status of this issue?

Apparently I'm not going to fix DMA controller engine if it even would
be fixed (I don't know what one you use), but I will continue with the
mentioned quirk as soon as I finish one higher priority task. Sorry for
a delay.

>  Just wondering, as this issue is listed
> in my regression reports for 4.7 and it seems nothing much happened
> for
> more than a week now â which is a bad sign as the 4.7 release seems
> only
> a week or two away.


-- 

Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy