Messages in this thread | | | Date | Thu, 6 Sep 2018 14:17:54 +0100 | From | Quentin Perret <> | Subject | Re: [PATCH] firmware: arm_scmi: fix divide by zero when sustained_perf_level is zero |
| |
Hi Sudeep,
On Wednesday 05 Sep 2018 at 17:38:11 (+0100), Sudeep Holla wrote: > @@ -166,7 +166,12 @@ scmi_perf_domain_attributes_get(const struct scmi_handle *handle, u32 domain, > le32_to_cpu(attr->sustained_freq_khz); > dom_info->sustained_perf_level = > le32_to_cpu(attr->sustained_perf_level); > - dom_info->mult_factor = (dom_info->sustained_freq_khz * 1000) / > + if (!dom_info->sustained_freq_khz || > + !dom_info->sustained_perf_level) > + dom_info->mult_factor = 1;
I'm sorry I missed that the first time I reviewed this patch, but after discussing with Ionela, we found out that there is actually a case where this could be a problem. If you have perf levels that are 1,2,3,4 (for example), then with mult_factor=1 you'll register OPPs at 1Hz, 2Hz, 3Hz, 4Hz into PM_OPP. And that will be turned into 0 KHz for all of them at the CPUFreq level when divided by 1000 in dev_pm_opp_init_cpufreq_table().
I guess a quick fix would be to have a default mult_factor of 1000 ...
What do you think ?
Thanks, Quentin
| |