* How is dmaengine_prep_slave_single supposed to be used?
@ 2012-01-27 14:32 Lars-Peter Clausen
2012-01-30 4:01 ` Vinod Koul
0 siblings, 1 reply; 2+ messages in thread
From: Lars-Peter Clausen @ 2012-01-27 14:32 UTC (permalink / raw)
To: Vinod Koul, Russell King; +Cc: linux-kernel@vger.kernel.org
Hi,
I've tried using dmaengine_prep_slave_single in one of my drivers an run
into an issue, the dma_address attribute of the sg element is not
initialized and thus the dma transfer and the DMA transfer fails.
Quoting from Documentation/dmaengine.txt:
The peripheral driver is expected to have mapped the scatterlist for
the DMA operation prior to calling device_prep_slave_sg, and must
keep the scatterlist mapped until the DMA operation has completed.
So this is clearly not the case with dmaengine_prep_slave_single, so I'm
wondering how is ut supposed to be used and can it work properly at all?
Thanks,
- Lars
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: How is dmaengine_prep_slave_single supposed to be used?
2012-01-27 14:32 How is dmaengine_prep_slave_single supposed to be used? Lars-Peter Clausen
@ 2012-01-30 4:01 ` Vinod Koul
0 siblings, 0 replies; 2+ messages in thread
From: Vinod Koul @ 2012-01-30 4:01 UTC (permalink / raw)
To: Lars-Peter Clausen; +Cc: Russell King, linux-kernel@vger.kernel.org
On Fri, 2012-01-27 at 15:32 +0100, Lars-Peter Clausen wrote:
> Hi,
>
> I've tried using dmaengine_prep_slave_single in one of my drivers an run
> into an issue, the dma_address attribute of the sg element is not
> initialized and thus the dma transfer and the DMA transfer fails.
>
> Quoting from Documentation/dmaengine.txt:
>
> The peripheral driver is expected to have mapped the scatterlist for
> the DMA operation prior to calling device_prep_slave_sg, and must
> keep the scatterlist mapped until the DMA operation has completed.
>
> So this is clearly not the case with dmaengine_prep_slave_single, so I'm
> wondering how is ut supposed to be used and can it work properly at all?
>
Yes this is broken now, I will fix this up
--
~Vinod
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2012-01-30 4:00 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-01-27 14:32 How is dmaengine_prep_slave_single supposed to be used? Lars-Peter Clausen
2012-01-30 4:01 ` Vinod Koul
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox