From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Guo Subject: Re: [PATCH v2] ARM: dts: imx6dl: disable dma support for spi on i.mx6dl Date: Tue, 16 Sep 2014 09:43:06 +0800 Message-ID: <20140916014304.GA23450@dragon> References: <1410327012-31185-1-git-send-email-b38343@freescale.com> <1410774073.3314.1.camel@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <1410774073.3314.1.camel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lucas Stach Cc: Robin Gong , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Mon, Sep 15, 2014 at 11:41:13AM +0200, Lucas Stach wrote: > Am Mittwoch, den 10.09.2014, 13:30 +0800 schrieb Robin Gong: > > There is one weird data in rxfifo after one full rx/tx transfer > > done sometimes. It looks a design issue and hard to workaround > > totally, so disable dma functhion here. And will re-enable it > > once the root cause found. > > > Sorry, I'm late to this as Shawn seems to already have picked up this > patch, but this isn't the right way to fix the problem. > > We made it clear at kernel summit last year that we try to not break > existing DTs as booting a new kernel with an old DT is a valid use case. > While you don't strictly violate this rule what you do here is only > fixing systems booting with a new DT while leaving others broken. > > If you are working around a hardware problem please disable DMA support > in the driver. This will also allow you to enable it again, if you find > another workaround without touching the DT again. Okay, it's a valid point. Patch dropped. Shawn -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html