This loop on EBCISR register was designed to clear IRQ sources before enabling a DMA channel. This register is clear-on-read so a race condition can appear if another channel is already active and has just finished its transfer. Removing this read on EBCISR is fixing the issue as there is no case where an IRQ could be pending: we already make sure that this register is drained at probe() time and during resume.
Signed-off-by: Nicolas Ferre <[email protected]> Cc: stable <[email protected]> --- drivers/dma/at_hdmac.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 7aa58d2..445fdf8 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -221,10 +221,6 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first) vdbg_dump_regs(atchan); - /* clear any pending interrupt */ - while (dma_readl(atdma, EBCISR)) - cpu_relax(); - channel_writel(atchan, SADDR, 0); channel_writel(atchan, DADDR, 0); channel_writel(atchan, CTRLA, 0); -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
