On 09/08/2022 14:33, Sam Protsenko wrote: > CMU_IS clock domain provides clocks for IS IP-core (Image Signal > Processing Subsystem). According to Exynos850 TRM, CMU_IS generates > CSIS, IPP, ITP, VRA and GDC clocks for BLK_IS. > > This patch adds next clocks: > - bus clocks in CMU_TOP needed for CMU_IS > - all internal CMU_IS clocks > - leaf clocks for IS IP-core, CSIS (Camera Serial Interface Slave), > D_TZPC (TrustZone Protection Controller), CSIS DMA, GDC (Geometric > Distortion Correction), IPP (Image Preprocessing Processing core), > ITP (Image Texture Processing core), MCSC (Multi-Channel Scaler), > VRA (Visual Recognition Accelerator), PPMU (Platform Performance > Monitoring Unit), SysMMU and SysReg > > IS related gate clocks in CMU_TOP were marked as CLK_IS_CRITICAL, > because: > 1. All of those have to be enabled in order to read > /sys/kernel/debug/clk/clk_summary file This sounds exactly like previous ISP clock hangs: https://lore.kernel.org/all/20171011092515.1698-1-m.szyprowski@xxxxxxxxxxx/ It looks like missing power domain references and your CLK_IS_CRITICAL is not correct. These are not critical clocks. > 2. When some user driver (e.g. exynos-sysmmu) disables some derived > leaf clock, it can lead to CMU_TOP clocks disable, which then makes > the system hang. To prevent that, the CLK_IS_CRITICAL flag is used, > as CLK_IGNORE_UNUSED is not enough. These are not critical clocks and usage of CLK_IS_CRITICAL is not appropriate. This looks like the same has as with other ISP, so it should be handled in similar way. Best regards, Krzysztof
