On Wed, 29 Apr 2020 at 17:50, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > On Friday, April 24, 2020 1:40:55 PM CEST Benjamin Gaignard wrote: > > When start streaming from the sensor the CPU load could remain very low > > because almost all the capture pipeline is done in hardware (i.e. without > > using the CPU) and let believe to cpufreq governor that it could use lower > > frequencies. If the governor decides to use a too low frequency that > > becomes a problem when we need to acknowledge the interrupt during the > > blanking time. > > The delay to ack the interrupt and perform all the other actions before > > the next frame is very short and doesn't allow to the cpufreq governor to > > provide the required burst of power. That led to drop the half of the frames. > > > > To avoid this problem, DCMI driver informs the cpufreq governors by adding > > a cpufreq minimum load QoS resquest. > > This seems to be addressing a use case that can be addressed with the help of > utilization clamps with less power overhead. Can't freq_qos_update_request() be also used if you don't have cgroup enabled on your system ? > > Thanks! > > >
