This is a note to let you know that I've just added the patch titled dmaengine: at_xdmac: Don't start transactions at tx_submit level to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dmaengine-at_xdmac-don-t-start-transactions-at-tx_submit-level.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bccfb96b59179d4f96cbbd1ddff8fac6d335eae4 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> Date: Wed, 15 Dec 2021 13:01:04 +0200 Subject: dmaengine: at_xdmac: Don't start transactions at tx_submit level From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> commit bccfb96b59179d4f96cbbd1ddff8fac6d335eae4 upstream. tx_submit is supposed to push the current transaction descriptor to a pending queue, waiting for issue_pending() to be called. issue_pending() must start the transfer, not tx_submit(), thus remove at_xdmac_start_xfer() from at_xdmac_tx_submit(). Clients of at_xdmac that assume that tx_submit() starts the transfer must be updated and call dma_async_issue_pending() if they miss to call it (one example is atmel_serial). As the at_xdmac_start_xfer() is now called only from at_xdmac_advance_work() when !at_xdmac_chan_is_enabled(), the at_xdmac_chan_is_enabled() check is no longer needed in at_xdmac_start_xfer(), thus remove it. Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver") Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211215110115.191749-2-tudor.ambarus@xxxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/dma/at_xdmac.c | 6 ------ 1 file changed, 6 deletions(-) --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -345,9 +345,6 @@ static void at_xdmac_start_xfer(struct a dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first); - if (at_xdmac_chan_is_enabled(atchan)) - return; - /* Set transfer as active to not try to start it again. */ first->active_xfer = true; @@ -431,9 +428,6 @@ static dma_cookie_t at_xdmac_tx_submit(s dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n", __func__, atchan, desc); list_add_tail(&desc->xfer_node, &atchan->xfers_list); - if (list_is_singular(&atchan->xfers_list)) - at_xdmac_start_xfer(atchan, desc); - spin_unlock_irqrestore(&atchan->lock, irqflags); return cookie; } Patches currently in stable-queue which might be from tudor.ambarus@xxxxxxxxxxxxx are queue-4.4/tty-serial-atmel-call-dma_async_issue_pending.patch queue-4.4/dmaengine-at_xdmac-don-t-start-transactions-at-tx_submit-level.patch queue-4.4/tty-serial-atmel-check-return-code-of-dmaengine_subm.patch