Hi Marek, 19. 3. 21. 오후 5:32에 Marek Szyprowski 이(가) 쓴 글: > Hi Inki, > > On 2019-03-21 09:20, Inki Dae wrote: >> 19. 3. 19. 오후 10:05에 Andrzej Hajda 이(가) 쓴 글: >>> MIXER on Exynos5 SoCs uses different synchronisation method than Exynos4 >>> to update internal state (shadow registers). >>> Apparently the driver implements it incorrectly. The rule should be >>> as follows: >>> - do not request updating registers until previous request was finished, >>> ie. MXR_CFG_LAYER_UPDATE_COUNT must be 0. >>> - before setting registers synchronisation on VSYNC should be turned off, >>> ie. MXR_STATUS_SYNC_ENABLE should be reset, >>> - after finishing MXR_STATUS_SYNC_ENABLE should be set again. >>> The patch hopefully implements it correctly. >>> Below sample kernel log from page fault caused by the bug: >>> >>> [ 25.670038] exynos-sysmmu 14650000.sysmmu: 14450000.mixer: PAGE FAULT occurred at 0x2247b800 >>> [ 25.677888] ------------[ cut here ]------------ >>> [ 25.682164] kernel BUG at ../drivers/iommu/exynos-iommu.c:450! >>> [ 25.687971] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM >>> [ 25.693778] Modules linked in: >>> [ 25.696816] CPU: 5 PID: 1553 Comm: fb-release_test Not tainted 5.0.0-rc7-01157-g5f86b1566bdd #136 >>> [ 25.705646] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) >>> [ 25.711710] PC is at exynos_sysmmu_irq+0x1c0/0x264 >>> [ 25.716470] LR is at lock_is_held_type+0x44/0x64 >>> >>> v2: added missing MXR_CFG_LAYER_UPDATE bit setting in mixer_enable_sync >>> >>> Reported-by: Marian Mihailescu <mihailescu2m@xxxxxxxxx> >>> Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx> >>> --- >>> Hi Inki and Marian, >>> >>> This is fixed version of my previous patch. The only difference is >>> added missing MXR_CFG_LAYER_UPDATE setting in mixer_enable_sync. >>> I hope this time it is correct. It should solve one page fault issue >>> in MIXER, Marek is preparing fix for another issue (to low clock set by >>> devfreq). I hope with both patches page faults will not happen anymore ;) >> With this patch modetest worked well. >> BTW, this change may affect Exynos4 series - which have different synchronization way to update shadow registers - so could you or someone else who has Exynos4xxx based board check it on Odroid-u3 board? I have no board. :( > > Andrzej's patch has been tested on Exynos4412 too. HDMI display works > fine on Odroid U3. Applied. Thanks, Inki Dae > > ... > > Best regards >
