This is a note to let you know that I've just added the patch titled
dmaengine: at_hdmac: remove clear-on-read in atc_dostart()
to the 3.0-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_hdmac-remove-clear-on-read-in-atc_dostart.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From ed8b0d67f33518a16c6b2450fe5ebebf180c2d04 Mon Sep 17 00:00:00 2001
From: Nicolas Ferre <[email protected]>
Date: Mon, 16 Apr 2012 14:46:30 +0200
Subject: dmaengine: at_hdmac: remove clear-on-read in atc_dostart()
From: Nicolas Ferre <[email protected]>
commit ed8b0d67f33518a16c6b2450fe5ebebf180c2d04 upstream.
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]>
Signed-off-by: Vinod Koul <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/dma/at_hdmac.c | 4 ----
1 file changed, 4 deletions(-)
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -237,10 +237,6 @@ static void atc_dostart(struct at_dma_ch
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);
Patches currently in stable-queue which might be from [email protected]
are
queue-3.0/dmaengine-at_hdmac-remove-clear-on-read-in-atc_dostart.patch
--
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
