linux-kernel - Re: [RFC] dmaengine: omap-dma: Start DMA without delay

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Message-ID: <20130329173100.GV30923@n2100.arm.linux.org.uk>
Date:	Fri, 29 Mar 2013 17:31:00 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Peter Ujfalusi <peter.ujfalusi@...com>
Cc:	Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>,
	Tony Lindgren <tony@...mide.com>, linux-kernel@...r.kernel.org,
	Felipe Balbi <balbi@...com>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
	Jarkko Nikula <jarkko.nikula@...mer.com>
Subject: Re: [RFC] dmaengine: omap-dma: Start DMA without delay

On Fri, Mar 29, 2013 at 03:12:03PM +0100, Peter Ujfalusi wrote:
> Remove the use of a tasklet to start the DMA channel when issue_pending is
> called.
> The use of tasklet delays the DMA start which can cause issues at drivers,
> for example the audio drivers expect that the DMA is started right away.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
> ---
> Hi Russell,
> 
> I know you are against removing the tasklet since you have planed to move the
> omap-dma to use runtime/dynamic DMA channel use.
> I have looked at the amba-pl08x.c driver which is doing that exactly (as you
> pointed out that to me). AMBA did not use tasklet either and I'm sure we can
> change the omap-dma driver to do the same in a same way as we could have done it
> with the tasklet use.

It's rather sad that you're ignoring what I'm saying, and going by what
another DMA engine driver - which is self contained - is doing, rather
than listening to my arguments against that approach.

I think in return I'll just ignore this patch, showing you the same
respect you show me.  Congratuations.
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