From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal =?UTF-8?B?U3VjaMOhbmVr?= Subject: Re: [PATCH 2/2] mmc: bcm2835: print some informational messages during reset Date: Sun, 4 Mar 2018 16:46:16 +0100 Message-ID: <20180304164616.75e8e55e@naga.suse.cz> References: <97593d6e1a41af1baff61f7d9e6e68a450fc9da6.1518619058.git.msuchanek@suse.de> <97593d6e1a41af1baff61f7d9e6e68a450fc9da6.1518619058.git.msuchanek@suse.de> <57ff1e429a7fc12300a3cca0c5e9a637beed0d3a.1518619058.git.msuchanek@suse.de> <20180214204733.7987d16c@naga.suse.cz> <1950058855.86123.1518718920111@email.1und1.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <1950058855.86123.1518718920111@email.1und1.de> Sender: linux-kernel-owner@vger.kernel.org To: Stefan Wahren Cc: Florian Fainelli , Scott Branden , linux-rpi-kernel@lists.infradead.org, Eric Anholt , bcm-kernel-feedback-list@broadcom.com, Gerd Hoffmann , linux-mmc@vger.kernel.org, Ulf Hansson , linux-kernel@vger.kernel.org, Ray Jui , "Gustavo A. R. Silva" , Julia Lawall , linux-arm-kernel@lists.infradead.org List-Id: linux-mmc@vger.kernel.org On Thu, 15 Feb 2018 19:22:00 +0100 (CET) Stefan Wahren wrote: > Hi Michal, > > > Michal Suchánek hat am 14. Februar 2018 um > > 20:47 geschrieben: > > > > > > On Wed, 14 Feb 2018 08:50:16 -0800 > > Florian Fainelli wrote: > > > > > On February 14, 2018 6:38:58 AM PST, Michal Suchanek > > > wrote: > > > >The previous patch does reset during hardware error so make the > > > >reset progress more visible. > > > > > > Based on your previous email it looks like this can happen quite > > > frequently so we might be spamming the kernel log with such reset > > > messages. Turning this into a debug print would not be great > > > either, how about a custom sysfs attribute counting the number of > > > times a reset was done? > > > > Since every such message happens when the system stalls for like > > half a minute I don't think there will be that many until somebody > > notices something is amiss. It might be also helpful in diagnosing > > if other cards lock up in different way - for me the DMA shutdown > > is short so I guess it's the mmc host that is locked up and the DMA > > engine is fine. It might look differently on different systems, > > though. > > FWIW according to your dmesg your RPi doesn't use the DMA engine: > > [ 5.004609] sdhost-bcm2835 3f202000.sdhost: unable to initialise DMA > channel. Falling back to PIO [ 5.154518] sdhost-bcm2835 > 3f202000.sdhost: loaded - DMA disabled > > For me it's a chicken and egg problem if the DMA driver is build as a > kernel module. It can be included in the ramdisk but somebody would have to add it to the list of required modules because the dependency is non-obvious. Thanks Michal