From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] omap: dma: Add read-back to DMA interrupt handler to avoid spurious interrupts Date: Fri, 5 Nov 2010 09:51:02 -0700 Message-ID: <20101105165102.GN9264@atomide.com> References: <1288017324-2181-1-git-send-email-mathias.nyman@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:62749 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752542Ab0KEQvS (ORCPT ); Fri, 5 Nov 2010 12:51:18 -0400 Content-Disposition: inline In-Reply-To: <1288017324-2181-1-git-send-email-mathias.nyman@nokia.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Mathias Nyman Cc: linux-omap@vger.kernel.org * Mathias Nyman [101025 07:22]: > Flush the writes to IRQSTATUS_L0 register in the DMA interrupt handler by reading the register > directly after write. This prevents the spurious DMA interrupts noted when using VDD_OPP 1 Adding this to omap-fixes. For future arch/arm/*omap*/ patches, please always Cc also linux-arm-kernel list. That way I can apply the patch without a need to repost. Regards, Tony > Signed-off-by: Mathias Nyman > --- > arch/arm/plat-omap/dma.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c > index f5c5b8d..2c28265 100644 > --- a/arch/arm/plat-omap/dma.c > +++ b/arch/arm/plat-omap/dma.c > @@ -1983,6 +1983,8 @@ static int omap2_dma_handle_ch(int ch) > > dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(ch)); > dma_write(1 << ch, IRQSTATUS_L0); > + /* read back the register to flush the write */ > + dma_read(IRQSTATUS_L0); > > /* If the ch is not chained then chain_id will be -1 */ > if (dma_chan[ch].chain_id != -1) { > -- > 1.5.6.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html