lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 17 Jan 2019 13:16:51 -0800 From: Guenter Roeck <groeck@...gle.com> To: Jerry.Hoemann@....com Cc: Stephen Boyd <swboyd@...omium.org>, Guenter Roeck <groeck@...omium.org>, Guenter Roeck <linux@...ck-us.net>, Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>, Wim Van Sebroeck <wim@...ux-watchdog.org>, linux-watchdog@...r.kernel.org, Rajendra Nayak <rnayak@...eaurora.org>, Vivek Gautam <vivek.gautam@...eaurora.org>, Sibi Sankar <sibis@...eaurora.org>, Doug Anderson <dianders@...omium.org>, linux-arm-kernel@...ts.infradead.org, linux-kernel <linux-kernel@...r.kernel.org>, linux-arm-msm@...r.kernel.org Subject: Re: [PATCHv2] watchdog: qcom: Add suspend/resume support On Thu, Jan 17, 2019 at 1:14 PM Jerry Hoemann <jerry.hoemann@....com> wrote: > > On Thu, Jan 17, 2019 at 11:09:31AM -0800, Guenter Roeck wrote: > > On Thu, Jan 17, 2019 at 10:37 AM Stephen Boyd <swboyd@...omium.org> wrote: > > > > > > Quoting Sai Prakash Ranjan (2019-01-17 07:19:42) > > > > diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c > > > > index 780971318810..5dfd604477a4 100644 > > > > --- a/drivers/watchdog/qcom-wdt.c > > > > +++ b/drivers/watchdog/qcom-wdt.c > > > > @@ -245,6 +245,28 @@ static int qcom_wdt_remove(struct platform_device *pdev) > > > > return 0; > > > > } > > > > > > > > +static int __maybe_unused qcom_wdt_suspend(struct device *dev) > > > > +{ > > > > + struct qcom_wdt *wdt = dev_get_drvdata(dev); > > > > + > > > > + if (watchdog_active(&wdt->wdd)) > > > > + qcom_wdt_stop(&wdt->wdd); > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +static int __maybe_unused qcom_wdt_resume(struct device *dev) > > > > +{ > > > > + struct qcom_wdt *wdt = dev_get_drvdata(dev); > > > > + > > > > + if (watchdog_active(&wdt->wdd)) > > > > + qcom_wdt_start(&wdt->wdd); > > > > + > > > > + return 0; > > > > +} > > > > > > This looks fairly generic. For example, the Mediatek driver also stops > > > and starts (but also pings after starting). Grepping for 'active' in > > > drivers/watchdog/ finds more examples. Could there be some functions in > > > watchdog core that do the common things like watchdog_stop() and > > > watchdog_start() and watchdog_start_and_ping()? Or maybe a bit can be > > > set during registration so that the 'struct class watchdog_class' can > > > get PM ops to stop and start on suspend/resume of the watchdog character > > > device? > > > > > > Nothing is wrong with the patch, I'm just bemoaning the amount of code > > > duplication here. > > > > > > > Patch(es) to add the functionality to the watchdog core are welcome; > > it should be possible to move the functionality into the core (maybe > > to be enabled with a new watchdog API call). Doing it using the class > > device sounds like an excellent idea. This should be straightforward > > to implement, though the question of "should we ping on resume or not" > > might be an endless source for bike shedding fun. > > > > Guenter > > It could be controlled by a currently unused bit in the > watchdog_info.options. Then people can agree to disagree. > I thought about that, but that would result in inconsistent behavior across drivers. Of course we could be all fancy and make it runtime configurable via ioctl. Guenter
Powered by blists - more mailing lists