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From: Bryan O'Donoghue <pure.logic@nexus-software.ie>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Vinod Koul <vinod.koul@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	dmaengine <dmaengine@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Puustinen, Ismo" <ismo.puustinen@intel.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>
Subject: Re: [PATCH v1 12/12] serial: 8250_lpss: enable DMA on Intel Quark UART
Date: Tue, 12 Apr 2016 17:25:20 +0100	[thread overview]
Message-ID: <1460478320.19152.92.camel@nexus-software.ie> (raw)
In-Reply-To: <CAHp75Vc3P=D47VtQ2JhbcMfx3xam0Bqp9gUW79jt32ThKzVULw@mail.gmail.com>

On Mon, 2016-04-11 at 18:51 +0300, Andy Shevchenko wrote:
> On Mon, Apr 11, 2016 at 6:33 PM, Bryan O'Donoghue
> <pure.logic@nexus-software.ie> wrote:
> > On Thu, 2016-04-07 at 23:37 +0300, Andy Shevchenko wrote:
> > 
> > Preface. I tried this on Galileo and it appears to work. I'll do
> > some
> > throughput testing to verify but, initially the results are
> > positive :)
> 
> I submitted (and pushed into my branch) a bit changed version (see my
> v2).
> 
> > > +       lpss->dma_maxburst = 8;
> > 
> > Are these dwords ? If those are bytes then the maxburst value looks
> > small. In the BSP the max burst is 32 bytes.
> 
> max_burst is in items of given size (here is 32 bytes for memory and 
> 8

I haven't read your V2 yet but on this, I'd suggest raising the burst
size to 32 bytes for UART (no higher) we found during bringup that
larger sizes "fall-over and die" but, anything up to 32 bytes is OK -
and therefore you should be able to reduce the number of
bursts/interrupts etc.

---
bod

  parent reply	other threads:[~2016-04-12 16:25 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-07 20:37 [PATCH v1 00/12] serial: 8250: split LPSS to 8250_lpss, enable DMA on Quark Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 01/12] dmaengine: dw: keep copy of custom slave config in dwc Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 02/12] dmaengine: dw: provide probe(), remove() stubs for users Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 03/12] dmaengine: dw: set polarity of handshake interface Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 04/12] dmaengine: dw: override LLP support if asked in platform data Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 05/12] serial: 8250_dma: switch to new dmaengine_terminate_* API Andy Shevchenko
2016-04-07 23:55   ` Peter Hurley
2016-04-07 20:37 ` [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on exception Andy Shevchenko
2016-04-07 23:54   ` Peter Hurley
2016-04-08  8:07     ` Andy Shevchenko
2016-04-08 23:20       ` Peter Hurley
2016-04-07 20:37 ` [PATCH v1 07/12] serial: 8250_dma: adjust DMA address of the UART Andy Shevchenko
2016-04-08  0:24   ` Peter Hurley
2016-04-07 20:37 ` [PATCH v1 08/12] serial: 8250: enable AFE on ports where FIFO is 16 bytes Andy Shevchenko
2016-04-07 23:43   ` Peter Hurley
2016-04-07 20:37 ` [PATCH v1 09/12] serial: 8250_lpss: split LPSS driver to separate module Andy Shevchenko
2016-04-08  1:42   ` Peter Hurley
2016-04-08  8:17     ` Andy Shevchenko
2016-04-08 22:44       ` Peter Hurley
2016-04-11 13:09         ` Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 10/12] serial: 8250_lpss: move Quark code from PCI driver Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 11/12] serial: 8250_lpss: enable MSI for Intel Quark Andy Shevchenko
2016-04-07 20:37 ` [PATCH v1 12/12] serial: 8250_lpss: enable DMA on Intel Quark UART Andy Shevchenko
2016-04-11 15:33   ` Bryan O'Donoghue
2016-04-11 15:51     ` Andy Shevchenko
2016-04-11 16:05       ` Andy Shevchenko
2016-04-12 16:25       ` Bryan O'Donoghue [this message]
2016-04-12 16:50         ` Andy Shevchenko
2016-04-13 11:22           ` Bryan O'Donoghue
2016-04-13 12:03             ` Andy Shevchenko
2016-04-13 14:34               ` Bryan O'Donoghue
2016-04-13 14:48                 ` Andy Shevchenko
2016-04-13 15:24                   ` Bryan O'Donoghue
2016-04-09 16:53 ` [PATCH v1 00/12] serial: 8250: split LPSS to 8250_lpss, enable DMA on Quark Bryan O'Donoghue
2016-04-09 17:48   ` Andy Shevchenko

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