From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v3 1/1] i2c: qcom-geni: Provide an option to disable DMA processing Date: Thu, 5 Sep 2019 15:33:45 +0100 Message-ID: <20190905143345.GF26880@dell> References: <20190905102247.27583-1-lee.jones@linaro.org> <20190905134941.GG1157@kunai> <3458ed2a-ae49-b46b-3e89-ce039a2749b4@axentia.se> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <3458ed2a-ae49-b46b-3e89-ce039a2749b4@axentia.se> Sender: linux-kernel-owner@vger.kernel.org To: Peter Rosin Cc: Wolfram Sang , "alokc@codeaurora.org" , "agross@kernel.org" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "bjorn.andersson@linaro.org" , "vkoul@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "devicetree@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Thu, 05 Sep 2019, Peter Rosin wrote: > On 2019-09-05 15:49, Wolfram Sang wrote: > > Hi Lee, > > > > I understand you are in a hurry, but please double check before > > sending... > > Linus indicated that an rc8 is coming up, which should provide an extra week. > https://lwn.net/Articles/798152/ That is good news. > > On Thu, Sep 05, 2019 at 11:22:47AM +0100, Lee Jones wrote: > >> We have a production-level laptop (Lenovo Yoga C630) which is exhibiting > >> a rather horrific bug. When I2C HID devices are being scanned for at > >> boot-time the QCom Geni based I2C (Serial Engine) attempts to use DMA. > >> When it does, the laptop reboots and the user never sees the OS. > >> > >> The beautiful thing about this approach is that, *if* the Geni SE DMA > >> ever starts working, we can remove the C code and any old properties > >> left in older DTs just become NOOP. Older kernels with newer DTs (less > >> of a priority) *still* will not work - but they do not work now anyway. > > > > ... becasue this paragraph doesn't fit anymore. Needs to be reworded. Yes, you're right. I noticed almost the moment I pressed send. :( > >> Fixes: 8bc529b25354 ("soc: qcom: geni: Add support for ACPI") > > > > As said in the other thread, I don't get it, but this is not a show > > stopper for me. Ah wait. Yes, this is applied against the wrong patch. Please ignore. > WAG: because ACPI made some driver load at all, and when it > did it something started happening which crashed some machines. I'm not sure I understand this sentence. ... resending now. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog