From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:13464 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753089AbcCAVmn (ORCPT ); Tue, 1 Mar 2016 16:42:43 -0500 Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-1.suw61.mandrillapp.com id hqo6d622rtkc for ; Tue, 1 Mar 2016 21:42:39 +0000 (envelope-from ) From: Subject: Patch "dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer" has been added to the 4.4-stable tree To: , , , , Cc: , Message-Id: <145686855619737@kroah.com> Date: Tue, 01 Mar 2016 21:42:38 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer 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-dw-disable-block-irqs-for-non-cyclic-xfer.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 know about it. >>From ee1cdcdae59563535485a5f56ee72c894ab7d7ad Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 10 Feb 2016 15:59:42 +0200 Subject: dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer From: Andy Shevchenko commit ee1cdcdae59563535485a5f56ee72c894ab7d7ad upstream. The commit 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks") re-enabled BLOCK interrupts with regard to make cyclic transfers work. However, this change becomes a regression for non-cyclic transfers as interrupt counters under stress test had been grown enormously (approximately per 4-5 bytes in the UART loop back test). Taking into consideration above enable BLOCK interrupts if and only if channel is programmed to perform cyclic transfer. Fixes: 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks") Signed-off-by: Andy Shevchenko Acked-by: Mans Rullgard Tested-by: Mans Rullgard Acked-by: Viresh Kumar Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/dw/core.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -156,7 +156,6 @@ static void dwc_initialize(struct dw_dma /* Enable interrupts */ channel_set_bit(dw, MASK.XFER, dwc->mask); - channel_set_bit(dw, MASK.BLOCK, dwc->mask); channel_set_bit(dw, MASK.ERROR, dwc->mask); dwc->initialized = true; @@ -588,6 +587,9 @@ static void dwc_handle_cyclic(struct dw_ spin_unlock_irqrestore(&dwc->lock, flags); } + + /* Re-enable interrupts */ + channel_set_bit(dw, MASK.BLOCK, dwc->mask); } /* ------------------------------------------------------------------------- */ @@ -618,11 +620,8 @@ static void dw_dma_tasklet(unsigned long dwc_scan_descriptors(dw, dwc); } - /* - * Re-enable interrupts. - */ + /* Re-enable interrupts */ channel_set_bit(dw, MASK.XFER, dw->all_chan_mask); - channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask); channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask); } @@ -1256,6 +1255,7 @@ static void dwc_free_chan_resources(stru int dw_dma_cyclic_start(struct dma_chan *chan) { struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma *dw = to_dw_dma(chan->device); unsigned long flags; if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) { @@ -1264,7 +1264,12 @@ int dw_dma_cyclic_start(struct dma_chan } spin_lock_irqsave(&dwc->lock, flags); + + /* Enable interrupts to perform cyclic transfer */ + channel_set_bit(dw, MASK.BLOCK, dwc->mask); + dwc_dostart(dwc, dwc->cdesc->desc[0]); + spin_unlock_irqrestore(&dwc->lock, flags); return 0; Patches currently in stable-queue which might be from andriy.shevchenko@linux.intel.com are queue-4.4/dmaengine-dw-disable-block-irqs-for-non-cyclic-xfer.patch