From mboxrd@z Thu Jan 1 00:00:00 1970 From: dkota@codeaurora.org Subject: Re: [PATCH V3] spi: spi-geni-qcom: Add SPI driver support for GENI based QUP Date: Mon, 10 Sep 2018 09:27:09 +0530 Message-ID: References: <1535107336-2214-1-git-send-email-dkota@codeaurora.org> <2493fc3fa3f6e5d2bcdde27cee1c33df@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Cc: Stephen Boyd , Mark Brown , Matthias Kaehlcke , LKML , linux-spi , Andy Gross , David Brown , Rob Herring , Mark Rutland , linux-arm-msm , "open list:ARM/QUALCOMM SUPPORT" , devicetree@vger.kernel.org, Girish Mahadevan To: Doug Anderson Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org >> I see there is no need of taking the spinlock as timeout will be >> handled >> after the calculated time as per data size and speed. >> There is 99.9% less chances of interrupt during the timeout handler. >>> >>> >>> >>> https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1201081 > > The thing is, we want it to be 100% reliable, not 99.9% reliable. Is > it somehow wrong to add the spinlock? ...or are you noticing > performance problems with the spinlock there? It's just nice not to > have to think about it. As I said, timeout will be handled after the calculated time as per data size and speed. Enough time is given for interrupt, there is no chance of interrupt occurrence during the handle_fifo_timeout(). So there is no need of spinlock.