Messages in this thread | | | Date | Fri, 3 Feb 2012 11:21:46 +0100 (CET) | From | Guennadi Liakhovetski <> | Subject | Re: [PATCH 1/7 v2] dmaengine: add a simple dma library |
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On Fri, 3 Feb 2012, Shimoda, Yoshihiro wrote:
> Hi Guennadi-san, > > 2012/02/03 7:19, Guennadi Liakhovetski wrote: > [ snip ] > >> > >> Thank you for your comment. > >> > >> I investigaed the issue. I found out the renesas_usbhs driver may > >> call tx_submit() in the callback() of the dma-simple finally. > > > > Sorry, in my first reply to this your email I misread the renesas_usbhs > > for an issue with your new SUDMAC driver. Since this is not the case and > > my patch seems to be causing a regression, I'll look at it. > > Thank you for the comment. > > I found out that if the "power_up" is 0 in the sample_tx_submit(), > the pm_state will be changed to "PENDING". > And then, even if the renesas_usbhs calls dma_async_issue_pending(), > the dma-simple driver doesn't call the simple_chan_xfer_ld_queue(). > This is because the driver will call the simple_chan_xfer_ld_queue() > when the pm_state is "ESTABLISHED" only. > > So I guess that we have to modify the simple_issue_pending().
Ok, I looked at this code, there's now a comment in simple_tx_submit():
if (power_up) { ... } else { /* * Tell .device_issue_pending() not to run the queue, interrupts * will do it anyway */ schan->pm_state = DMA_SIMPLE_PM_PENDING; }
And that's exactly what should be happening: an interrupt should trigger the IRQ thread should call simple_chan_xfer_ld_queue(), so, looks like the interrupt is not coming? It's also strange, why and how it worked without dma-simple? I don't think I changed that with the transition... Investigating.
Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/
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