Messages in this thread | | | Date | Fri, 6 Jan 2012 13:43:11 +0100 | From | Sascha Hauer <> | Subject | Re: [PATCH 1/2] dmaengine: Fix status handling in imx-dma. |
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On Fri, Jan 06, 2012 at 04:40:24PM +0530, Vinod Koul wrote: > On Fri, 2012-01-06 at 10:37 +0100, Sascha Hauer wrote: > > On Fri, Jan 06, 2012 at 11:26:29AM +0530, Vinod Koul wrote: > > > On Mon, 2012-01-02 at 13:18 +0100, Javier Martin wrote: > > > > Status must only be changed to DMA_IN_PROGRESS > > > > when the DMA transfer has really begun. > > > > > > > > However, since this driver lacks of support for > > > > multiple descriptors a new flag has to be introduced > > > > to avoid the prepare function be called multiple times. > > > Thanks this is the right approach to fix this driver > > > > > > But this will obviously break any users of this driver as they need to > > > call the right APIs now :D > > > > > > Sacha: can you check this patch and see which users of this driver will > > > break. we need those fixes to go along this patch as well > > > > Which users should break? I just tried with the mxcmmc driver and this > > one does not break. > > > > I do not really understand this patch anyway. It changes imxdmac->status > > to a write-only variable and introduces a imxdmac->prepared variable > > with the same meaning. This patch is a complicated no-op. > > > > What was the original problem? The fact that we used a enum dma_status > > with the wrong semantics? In that case I suggest to simply replace this > > variable. All we need to track is that we do not enter > > imxdma_prep_slave_sg with an already running transfer. > the memcpy patch submitted earlier didn't use correct dmaengine API. a > descriptor is not supposed to be started in prepare. The reason given > was the driver already does so for all other prepares, so i suggested to > fix that. Descriptors should be started in issue_pending only.
The transfer is not started in prepare but in imxdmac->desc.tx_submit
Sascha
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