On 10/30/22 20:30, Heiko Stuebner wrote: > Hi Johan, > > Am Sonntag, 30. Oktober 2022, 19:36:01 CET schrieb Johan Jonker: >> The clocksource and the sched_clock provided by the arm_global_timer >> on Rockchip rk3066a/rk3188 are quite unstable because their rates >> depend on the cpu frequency. >> >> Recent changes to the arm_global_timer driver makes it impossible to use. >> >> On the other side, the arm_global_timer has a higher rating than the >> rockchip_timer, it will be selected by default by the time framework >> while we want to use the stable rockchip clocksource. >> >> Let's disable the arm_global_timer in order to have the ROCKCHIP_TIMER >> (rk3188) or DW_APB_TIMER (rk3066a) selected by default. > > Doing that change won't help you with the issue you see. > These days kernel images are supposed to run on as many > platforms as possible with the _same_ kernel image. > > So the muliplatform image build from the kernel's defconfig will > include most of the time other platforms that will pull in the > global-timer again. > > How about "imply" instead of "select"? It's no longer useful. One can get rid of if one wants a really lean kernel. > I do see that you disable the global-timer > in the rk3066 dtsi in patch2, though this would leave the rk3188 > still using the global-timer. Why not do this in the rk3xxx.dtsi? > > I.e. keep the global-timer node, but add a disabled property > together with a comment above the status=disabled, describing > the issue. [This should keep people from re-adding the global-timer > in the future :-) ] > > Thanks > Heiko > >> Signed-off-by: Johan Jonker <jbx6244@xxxxxxxxx> >> --- >> >> ARM: dts: rockchip: disable arm-global-timer for rk3188 >> https://lore.kernel.org/linux-rockchip/1492374441-23336-26-git-send-email-daniel.lezcano@xxxxxxxxxx/ >> >> clocksource: arm_global_timer: implement rate compensation whenever source clock changes >> https://lore.kernel.org/all/20210406130045.15491-2-andrea.merello@xxxxxxxxx/ >> --- >> arch/arm/mach-rockchip/Kconfig | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig >> index b7855cc66..0432a4430 100644 >> --- a/arch/arm/mach-rockchip/Kconfig >> +++ b/arch/arm/mach-rockchip/Kconfig >> @@ -15,8 +15,6 @@ config ARCH_ROCKCHIP >> select DW_APB_TIMER_OF >> select REGULATOR if PM >> select ROCKCHIP_TIMER >> - select ARM_GLOBAL_TIMER >> - select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK >> select ZONE_DMA if ARM_LPAE >> select PM >> help >> -- >> 2.20.1 >> >> > > > >
