Messages in this thread | | | From | Appana Durga Kedareswara Rao <> | Subject | RE: [PATCH 1/3] dmaengine: xilinx_dma: Check for channel idle state before submitting dma descriptor | Date | Mon, 19 Dec 2016 15:39:43 +0000 |
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Hi Laurent Pinchart,
Thanks for the review...
> > > > + if (!chan->idle) > > + return; > > Don't you need to perform the same check for the DMA and CDMA channels ? If > so, shouldn't this be moved to common code ?
Will fix it in v2...
> > There's another problem (not strictly introduced by this patch) I wanted to > mention. The append_desc_queue() function, called from your tx_submit > handler, appends descriptors to the pending_list. The DMA engine API states > that a transfer submitted by tx_submit will not be executed until .issue_pending() > is called. However, if a transfer is in progress at tx_submit time, I believe that > the IRQ handler, at transfer completion, will start the next transfer from the > pending_list even if .issue_pending() hasn't been called for it. > > > if (list_empty(&chan->pending_list)) > > return;
If user submits more than h/w limit then that case only driver will process The descriptors from the pending_list for other cases the pending_list will be Empty so driver just returns from there.
> > Now that you catch busy channels with a software flag, do you still need the > xilinx_dma_is_running() and xilinx_dma_is_idle() checks ? Three different checks > for the same or very similar conditions are confusing, if you really need them > you should document clearly how they differ.
Will remove the xilinx_dma_is_running and xilinx_dmais_idle() checks and will use Chan->idle check across all the IP's. Will fix it v2...
> > > @@ -1110,6 +1116,7 @@ static void xilinx_vdma_start_transfer(struct > > xilinx_dma_chan *chan) vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, > > last->hw.vsize); > > } > > > > + chan->idle = false; > > (and this too)
Will fix in v2...
Regards, Kedar.
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