09.07.2020 20:35, Dmitry Osipenko пишет: > The enter() callback of CPUIDLE drivers returns index of the entered idle > state on success or a negative value on failure. The negative value could > any negative value, i.e. it doesn't necessarily needs to be a error code. > That's because CPUIDLE core only cares about the fact of failure and not > about the reason of the enter() failure. > > Like every other enter() callback, the arm_cpuidle_simple_enter() returns > the entered idle-index on success. Unlike some of other drivers, it never > fails. It happened that TEGRA_C1=index=err=0 in the code of cpuidle-tegra > driver, and thus, there is no problem for the cpuidle-tegra driver created > by the typo in the code which assumes that the arm_cpuidle_simple_enter() > returns a error code. > > The arm_cpuidle_simple_enter() also may return a -ENODEV error if CPU_IDLE > is disabled in a kernel's config, but all CPUIDLE drivers are disabled if > CPU_IDLE is disabled, including the cpuidle-tegra driver. So we can't ever > see the error code from arm_cpuidle_simple_enter() today. > > Of course the code may get some changes in the future and then the > typo may transform into a real bug, so let's correct the typo! The > tegra_cpuidle_state_enter() is now changed to make it return the entered > idle-index on success and negative error code on fail, which puts it on > par with the arm_cpuidle_simple_enter(), making code consistent in regards > to the error handling. > > This patch fixes a minor typo in the code, it doesn't fix any bugs. > > Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> > --- > > Changelog: > > v3: The tegra_cpuidle_state_enter() now returns entered idle-index on > success instead of 0. Hence the error message will be shown by the > tegra-cpuidle driver if arm_cpuidle_simple_enter() will ever fail. > Again thanks to Jon Hunter! Hello, Jon! Do you see anything else that could be improved in this patch?
