This is a note to let you know that I've just added the patch titled dmaengine: hsu: correct residue calculation of active descriptor to the 4.5-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-hsu-correct-residue-calculation-of-active-descriptor.patch and it can be found in the queue-4.5 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a197f3c7d48c0c1f45076ea47533a76ba9b1a959 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Date: Fri, 18 Mar 2016 14:26:33 +0200 Subject: dmaengine: hsu: correct residue calculation of active descriptor From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> commit a197f3c7d48c0c1f45076ea47533a76ba9b1a959 upstream. The commit f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation") speeded up calculation of the queued descriptor but broke the initial residue value for active descriptor. In accordance with documentation the hardware descriptor is updated each time DMA transfered some bytes. It means we have to calculate a sum of lengths of non-submitted hardware descriptors and whatever current values in the hardware. Do this straightforward. Fixes: f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation") Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/dma/hsu/hsu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/dma/hsu/hsu.c +++ b/drivers/dma/hsu/hsu.c @@ -254,10 +254,13 @@ static void hsu_dma_issue_pending(struct static size_t hsu_dma_active_desc_size(struct hsu_dma_chan *hsuc) { struct hsu_dma_desc *desc = hsuc->desc; - size_t bytes = desc->length; + size_t bytes = 0; int i; - i = desc->active % HSU_DMA_CHAN_NR_DESC; + for (i = desc->active; i < desc->nents; i++) + bytes += desc->sg[i].len; + + i = HSU_DMA_CHAN_NR_DESC - 1; do { bytes += hsu_chan_readl(hsuc, HSU_CH_DxTSR(i)); } while (--i >= 0); Patches currently in stable-queue which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are queue-4.5/dmaengine-hsu-correct-use-of-channel-status-register.patch queue-4.5/dmaengine-hsu-correct-residue-calculation-of-active-descriptor.patch queue-4.5/dmaengine-dw-fix-master-selection.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html