From: Nicola Mazzucato <nicola.mazzucato@arm.com> To: Viresh Kumar <viresh.kumar@linaro.org> Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vireshk@kernel.org, robh+dt@kernel.org, sboyd@kernel.org, nm@ti.com, daniel.lezcano@linaro.org, morten.rasmussen@arm.com, chris.redpath@arm.com Subject: Re: [PATCH v4 3/4] scmi-cpufreq: get opp_shared_cpus from opp-v2 for EM Date: Tue, 8 Dec 2020 10:58:44 +0000 [thread overview] Message-ID: <83b8400f-8dc4-000e-d790-0bf584a75f48@arm.com> (raw) In-Reply-To: <20201208072611.ptsqupv4y2wybs6p@vireshk-i7> On 12/8/20 7:26 AM, Viresh Kumar wrote: > On 08-12-20, 07:22, Nicola Mazzucato wrote: >> On 12/8/20 5:50 AM, Viresh Kumar wrote: >>> On 02-12-20, 17:23, Nicola Mazzucato wrote: >>>> nr_opp = dev_pm_opp_get_opp_count(cpu_dev); >>>> if (nr_opp <= 0) { >>>> - dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); >>>> - ret = -EPROBE_DEFER; >>>> - goto out_free_opp; >>>> + ret = handle->perf_ops->device_opps_add(handle, cpu_dev); >>>> + if (ret) { >>>> + dev_warn(cpu_dev, "failed to add opps to the device\n"); >>>> + goto out_free_cpumask; >>>> + } >>>> + >>>> + ret = dev_pm_opp_set_sharing_cpus(cpu_dev, opp_shared_cpus); >>>> + if (ret) { >>>> + dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", >>>> + __func__, ret); >>>> + goto out_free_cpumask; >>>> + } >>>> + >>> >>> Why do we need to call above two after calling >>> dev_pm_opp_get_opp_count() ? >> >> Sorry, I am not sure to understand your question here. If there are no opps for >> a device we want to add them to it > > Earlier we used to call handle->perf_ops->device_opps_add() and > dev_pm_opp_set_sharing_cpus() before calling dev_pm_opp_get_opp_count(), why is > the order changed now ? True. The order has changed to take into account the fact that when we have per-cpu + opp-shared, we don't need to add opps for devices which already have them. > >> otherwise no need as they would be duplicated. > > I am not sure why they would be duplicated in your case. I though > device_opps_add() is responsible for dynamically adding the OPPs here. In case of per-cpu + opp-shared, with the "previous order" we would try to add opps to a device which already has them, in fact attempting to add duplicates. Nothing wrong with it, but a lot of warnings are thrown. > >>> And we don't check the return value of >>> the below call anymore, moreover we have to call it twice now. >> >> This second get_opp_count is required such that we register em with the correct >> opp number after having added them. Without this the opp_count would not be correct. > > What if the count is still 0 ? What about deferred probe we were doing earlier ? My assumption is to rely on the two above to fail if there was something wrong. For the deferred probe, I am not sure it is still a useful case to have, but I will let Sudeep have his view also on this. > Thanks Viresh, hope it's a bit more clear now. Nicola
WARNING: multiple messages have this Message-ID (diff)
From: Nicola Mazzucato <nicola.mazzucato@arm.com> To: Viresh Kumar <viresh.kumar@linaro.org> Cc: nm@ti.com, devicetree@vger.kernel.org, linux-pm@vger.kernel.org, sboyd@kernel.org, vireshk@kernel.org, daniel.lezcano@linaro.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, robh+dt@kernel.org, sudeep.holla@arm.com, chris.redpath@arm.com, morten.rasmussen@arm.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 3/4] scmi-cpufreq: get opp_shared_cpus from opp-v2 for EM Date: Tue, 8 Dec 2020 10:58:44 +0000 [thread overview] Message-ID: <83b8400f-8dc4-000e-d790-0bf584a75f48@arm.com> (raw) In-Reply-To: <20201208072611.ptsqupv4y2wybs6p@vireshk-i7> On 12/8/20 7:26 AM, Viresh Kumar wrote: > On 08-12-20, 07:22, Nicola Mazzucato wrote: >> On 12/8/20 5:50 AM, Viresh Kumar wrote: >>> On 02-12-20, 17:23, Nicola Mazzucato wrote: >>>> nr_opp = dev_pm_opp_get_opp_count(cpu_dev); >>>> if (nr_opp <= 0) { >>>> - dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); >>>> - ret = -EPROBE_DEFER; >>>> - goto out_free_opp; >>>> + ret = handle->perf_ops->device_opps_add(handle, cpu_dev); >>>> + if (ret) { >>>> + dev_warn(cpu_dev, "failed to add opps to the device\n"); >>>> + goto out_free_cpumask; >>>> + } >>>> + >>>> + ret = dev_pm_opp_set_sharing_cpus(cpu_dev, opp_shared_cpus); >>>> + if (ret) { >>>> + dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", >>>> + __func__, ret); >>>> + goto out_free_cpumask; >>>> + } >>>> + >>> >>> Why do we need to call above two after calling >>> dev_pm_opp_get_opp_count() ? >> >> Sorry, I am not sure to understand your question here. If there are no opps for >> a device we want to add them to it > > Earlier we used to call handle->perf_ops->device_opps_add() and > dev_pm_opp_set_sharing_cpus() before calling dev_pm_opp_get_opp_count(), why is > the order changed now ? True. The order has changed to take into account the fact that when we have per-cpu + opp-shared, we don't need to add opps for devices which already have them. > >> otherwise no need as they would be duplicated. > > I am not sure why they would be duplicated in your case. I though > device_opps_add() is responsible for dynamically adding the OPPs here. In case of per-cpu + opp-shared, with the "previous order" we would try to add opps to a device which already has them, in fact attempting to add duplicates. Nothing wrong with it, but a lot of warnings are thrown. > >>> And we don't check the return value of >>> the below call anymore, moreover we have to call it twice now. >> >> This second get_opp_count is required such that we register em with the correct >> opp number after having added them. Without this the opp_count would not be correct. > > What if the count is still 0 ? What about deferred probe we were doing earlier ? My assumption is to rely on the two above to fail if there was something wrong. For the deferred probe, I am not sure it is still a useful case to have, but I will let Sudeep have his view also on this. > Thanks Viresh, hope it's a bit more clear now. Nicola _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-08 10:57 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-02 17:23 [PATCH v4 0/4] CPUFreq: Add support for opp-sharing cpus Nicola Mazzucato 2020-12-02 17:23 ` Nicola Mazzucato 2020-12-02 17:23 ` [PATCH v4 1/4] dt-bindings/opp: Update documentation for opp-shared Nicola Mazzucato 2020-12-02 17:23 ` Nicola Mazzucato 2020-12-08 4:29 ` Viresh Kumar 2020-12-08 4:29 ` Viresh Kumar 2020-12-08 7:15 ` Nicola Mazzucato 2020-12-08 7:15 ` Nicola Mazzucato 2020-12-02 17:23 ` [PATCH v4 2/4] opp/of: Allow empty opp-table with opp-shared Nicola Mazzucato 2020-12-02 17:23 ` Nicola Mazzucato 2020-12-02 17:23 ` [PATCH v4 3/4] scmi-cpufreq: get opp_shared_cpus from opp-v2 for EM Nicola Mazzucato 2020-12-02 17:23 ` Nicola Mazzucato 2020-12-08 5:50 ` Viresh Kumar 2020-12-08 5:50 ` Viresh Kumar 2020-12-08 7:22 ` Nicola Mazzucato 2020-12-08 7:22 ` Nicola Mazzucato 2020-12-08 7:26 ` Viresh Kumar 2020-12-08 7:26 ` Viresh Kumar 2020-12-08 10:58 ` Nicola Mazzucato [this message] 2020-12-08 10:58 ` Nicola Mazzucato 2020-12-08 11:01 ` Viresh Kumar 2020-12-08 11:01 ` Viresh Kumar 2020-12-08 11:21 ` Sudeep Holla 2020-12-08 11:21 ` Sudeep Holla 2020-12-08 11:20 ` Sudeep Holla 2020-12-08 11:20 ` Sudeep Holla 2020-12-08 11:34 ` Lukasz Luba 2020-12-08 11:34 ` Lukasz Luba 2020-12-08 12:22 ` Sudeep Holla 2020-12-08 12:22 ` Sudeep Holla 2020-12-08 13:17 ` Nicola Mazzucato 2020-12-08 13:17 ` Nicola Mazzucato 2020-12-09 5:45 ` Viresh Kumar 2020-12-09 5:45 ` Viresh Kumar 2020-12-09 9:20 ` Nicola Mazzucato 2020-12-09 9:20 ` Nicola Mazzucato 2020-12-09 9:41 ` Sudeep Holla 2020-12-09 9:41 ` Sudeep Holla 2020-12-02 17:23 ` [PATCH v4 4/4] cpufreq: blacklist Arm Vexpress platforms in cpufreq-dt-platdev Nicola Mazzucato 2020-12-02 17:23 ` Nicola Mazzucato
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