From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alim Akhtar Subject: Re: [PATCH v2 0/6] Switch to generic syscon regmap based drivers Date: Wed, 21 Oct 2015 20:26:07 +0530 Message-ID: References: <1445333085-22837-1-git-send-email-alim.akhtar@samsung.com> <1606098.olLAyTIhB3@dell2.five-lan.de> <56272C1C.8040007@samsung.com> <562765F3.9010306@osg.samsung.com> <56276C87.6040509@samsung.com> <562791D4.3050105@osg.samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <562791D4.3050105-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Javier Martinez Canillas Cc: Alim Akhtar , Markus Reichl , "linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , kgene , =?UTF-8?Q?Krzysztof_Koz=C5=82owski?= , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Tobias Jakobi List-Id: devicetree@vger.kernel.org Hi Javier, On Wed, Oct 21, 2015 at 6:53 PM, Javier Martinez Canillas wrote: > Hello Alim, > > On 10/21/2015 12:44 PM, Alim Akhtar wrote: > > [snip] > >>> >>> Can you please test following patch [0] on top of Alim's series? If that >>> works then it should either be part of Alim's series or the patches will >>> have to wait until that patch lands into mainline. I don't have an eMMC >>> to test it in XU4 but I'm pretty confident that it will solve the issue. >>> >> I am fine with including this with my series or lowering syscon_restart_handler priority to 128. > > Yes, I also considered changing the syscon-reboot handler priority to 128 but > then I noticed this commit: > > b81180b3fd48 ("power: reset: adjust priority of simple syscon reboot driver"). > > So as you can see, it was 128 before but was bumped to 192 so it was called > before restart handlers registered by watchdogs. So, changing to 128 would > break other people use cases. > > Now, I don't know if that is the right fix since register_restart_handler() > explanation about the policy used for restart handler priority numbers is > scarce. It only mentions 0, 128 and 255 so probably the correct thing to do > is to change all watchdog restart handler to 0 but that is a separate issue. > >> It also make sense to increase eMMC priority as you suggested as before system reboot, devices should have reseted itself. > > That was my rationale as well and is why I think the handler for devices > should use the highest priority regardless if the syscon-reboot is later > changed to prio 128 and the watchdog handlers to 0. > I agree, in any case dumping up eMMC reset priority make sense. If all is good here, over to Krzysztof and Ulf to handle these patches. Thanks. > Best regards, > > [0]: http://lxr.free-electrons.com/source/kernel/reboot.c#L113 > > Best regards, > -- > Javier Martinez Canillas > Open Source Group > Samsung Research America -- Regards, Alim -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: alim.akhtar@gmail.com (Alim Akhtar) Date: Wed, 21 Oct 2015 20:26:07 +0530 Subject: [PATCH v2 0/6] Switch to generic syscon regmap based drivers In-Reply-To: <562791D4.3050105@osg.samsung.com> References: <1445333085-22837-1-git-send-email-alim.akhtar@samsung.com> <1606098.olLAyTIhB3@dell2.five-lan.de> <56272C1C.8040007@samsung.com> <562765F3.9010306@osg.samsung.com> <56276C87.6040509@samsung.com> <562791D4.3050105@osg.samsung.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Javier, On Wed, Oct 21, 2015 at 6:53 PM, Javier Martinez Canillas wrote: > Hello Alim, > > On 10/21/2015 12:44 PM, Alim Akhtar wrote: > > [snip] > >>> >>> Can you please test following patch [0] on top of Alim's series? If that >>> works then it should either be part of Alim's series or the patches will >>> have to wait until that patch lands into mainline. I don't have an eMMC >>> to test it in XU4 but I'm pretty confident that it will solve the issue. >>> >> I am fine with including this with my series or lowering syscon_restart_handler priority to 128. > > Yes, I also considered changing the syscon-reboot handler priority to 128 but > then I noticed this commit: > > b81180b3fd48 ("power: reset: adjust priority of simple syscon reboot driver"). > > So as you can see, it was 128 before but was bumped to 192 so it was called > before restart handlers registered by watchdogs. So, changing to 128 would > break other people use cases. > > Now, I don't know if that is the right fix since register_restart_handler() > explanation about the policy used for restart handler priority numbers is > scarce. It only mentions 0, 128 and 255 so probably the correct thing to do > is to change all watchdog restart handler to 0 but that is a separate issue. > >> It also make sense to increase eMMC priority as you suggested as before system reboot, devices should have reseted itself. > > That was my rationale as well and is why I think the handler for devices > should use the highest priority regardless if the syscon-reboot is later > changed to prio 128 and the watchdog handlers to 0. > I agree, in any case dumping up eMMC reset priority make sense. If all is good here, over to Krzysztof and Ulf to handle these patches. Thanks. > Best regards, > > [0]: http://lxr.free-electrons.com/source/kernel/reboot.c#L113 > > Best regards, > -- > Javier Martinez Canillas > Open Source Group > Samsung Research America -- Regards, Alim