Re: [PATCH] dmaengine: ti: omap-dma: Configure LCH_TYPE for OMAP1

From: Aaro Koskinen
Date: Thu Nov 22 2018 - 17:24:32 EST


Hi,

On Thu, Nov 22, 2018 at 03:12:36PM +0000, Russell King - ARM Linux wrote:
> On Thu, Nov 22, 2018 at 10:29:48AM +0000, Russell King - ARM Linux wrote:
> > On Tue, Nov 20, 2018 at 11:04:06PM +0200, Aaro Koskinen wrote:
> > > I had switched to PIO mode in 2015 since the WARNs about legacy DMA
> > > API were too annoying and flooding the console. And now that I tried
> > > using DMA again with g_ether, it doesn't work anymore. The device get's
> > > recognized on host side, but no traffic goes through. Switching back to
> > > PIO makes it to work again.
> >
> > A solution to that would be to do what the warning message says, and
> > update the driver to the DMAengine API.

Fully agreed, but I was busy debugging other more serious issues, and
just wanted to get a reliable ssh or USB serial access to the device
without any extra noise, so switching to PIO using a module parameter
is probably what most users do in such situations.

> Here's a partial conversion (not even build tested) - it only supports
> OUT transfers with dmaengine at the moment.

Thanks, I'll take a closer look and try to do some testing hopefully
during the weekend.

A.