From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH] dmaengine: shdma: Runtime-resume device in .shutdown() Date: Fri, 5 Dec 2014 23:17:54 +0530 Message-ID: <20141205174754.GV3411@intel.com> References: <1416410146-29652-1-git-send-email-geert+renesas@glider.be> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1416410146-29652-1-git-send-email-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org To: Geert Uytterhoeven Cc: Dan Williams , dmaengine@vger.kernel.org, linux-pm@vger.kernel.org, linux-sh@vger.kernel.org List-Id: linux-pm@vger.kernel.org On Wed, Nov 19, 2014 at 04:15:46PM +0100, Geert Uytterhoeven wrote: > During system reboot, the sh-dma-engine device may be runtime-suspended, > causing a crash: > > Unhandled fault: imprecise external abort (0x1406) at 0x0002c02c > Internal error: : 1406 [#1] SMP ARM > ... > PC is at sh_dmae_ctl_stop+0x28/0x64 > LR is at sh_dmae_ctl_stop+0x24/0x64 > > If the sh-dma-engine is runtime-suspended, its module clock is turned > off, and its registers cannot be accessed. Runtime-resume the device in > the driver's .shutdown() callback to fix this. > > Signed-off-by: Geert Uytterhoeven > --- > drivers/dma/sh/shdmac.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/dma/sh/shdmac.c b/drivers/dma/sh/shdmac.c > index b65317c6ea4e722c..a13c6ba7468f12a6 100644 > --- a/drivers/dma/sh/shdmac.c > +++ b/drivers/dma/sh/shdmac.c > @@ -585,7 +585,10 @@ static void sh_dmae_chan_remove(struct sh_dmae_device *shdev) > static void sh_dmae_shutdown(struct platform_device *pdev) > { > struct sh_dmae_device *shdev = platform_get_drvdata(pdev); > + > + pm_runtime_get_sync(&pdev->dev); > sh_dmae_ctl_stop(shdev); > + pm_runtime_put(&pdev->dev); but if you are runtime_suspended, then why should you even proceed to stop the clock. Why not just cleanup and return when runtime suspended -- ~Vinod