https://bugs.freedesktop.org/show_bug.cgi?id=101575
--- Comment #3 from Hi-Angel Hi-Angel@yandex.ru --- Some more info: for hard lockup SysRq and network stops working. I managed to get a trace for hard lockup using netconsole before network disappeared. An interesting part may be "Wait for MC idle timedout !" — I never saw it before.
[ 3943.482116] radeon 0000:01:00.0: ring 0 stalled for more than 10030msec [ 3943.482135] radeon 0000:01:00.0: GPU lockup (current fence id 0x0000000000026550 last fence id 0x000000000002657b on ring 0) [ 3943.482214] radeon 0000:01:00.0: failed to get a new IB (-35) [ 3943.482269] [drm:radeon_cs_ioctl [radeon]] *ERROR* Failed to get ib ! [ 3943.489601] radeon 0000:01:00.0: Saved 1474 dwords of commands on ring 0. [ 3943.489623] radeon 0000:01:00.0: GPU softreset: 0x0000009D [ 3943.489629] radeon 0000:01:00.0: GRBM_STATUS = 0xA0631CA0 [ 3943.489634] radeon 0000:01:00.0: GRBM_STATUS_SE0 = 0x18000003 [ 3943.489639] radeon 0000:01:00.0: GRBM_STATUS_SE1 = 0x00000007 [ 3943.489644] radeon 0000:01:00.0: SRBM_STATUS = 0x200046C0 [ 3943.489649] radeon 0000:01:00.0: SRBM_STATUS2 = 0x00000000 [ 3943.489654] radeon 0000:01:00.0: R_008674_CP_STALLED_STAT1 = 0x01000000 [ 3943.489660] radeon 0000:01:00.0: R_008678_CP_STALLED_STAT2 = 0x00011000 [ 3943.489665] radeon 0000:01:00.0: R_00867C_CP_BUSY_STAT = 0x00068402 [ 3943.489670] radeon 0000:01:00.0: R_008680_CP_STAT = 0x80870243 [ 3943.489675] radeon 0000:01:00.0: R_00D034_DMA_STATUS_REG = 0x60C83146 [ 3943.497932] radeon 0000:01:00.0: GRBM_SOFT_RESET=0x00007F6B [ 3943.498011] radeon 0000:01:00.0: SRBM_SOFT_RESET=0x00108100 [ 3943.499187] radeon 0000:01:00.0: GRBM_STATUS = 0xC0003828 [ 3943.499196] radeon 0000:01:00.0: GRBM_STATUS_SE0 = 0x80000007 [ 3943.499202] radeon 0000:01:00.0: GRBM_STATUS_SE1 = 0x00000007 [ 3943.499207] radeon 0000:01:00.0: SRBM_STATUS = 0x20000CC0 [ 3943.499212] radeon 0000:01:00.0: SRBM_STATUS2 = 0x00000000 [ 3943.499218] radeon 0000:01:00.0: R_008674_CP_STALLED_STAT1 = 0x00000000 [ 3943.499223] radeon 0000:01:00.0: R_008678_CP_STALLED_STAT2 = 0x00000000 [ 3943.499228] radeon 0000:01:00.0: R_00867C_CP_BUSY_STAT = 0x00000000 [ 3943.499233] radeon 0000:01:00.0: R_008680_CP_STAT = 0x00000000 [ 3943.499239] radeon 0000:01:00.0: R_00D034_DMA_STATUS_REG = 0x44C83D57 [ 3943.499261] radeon 0000:01:00.0: GPU reset succeeded, trying to resume [ 3943.499355] radeon 0000:01:00.0: GPU softreset: 0x00000001 [ 3943.499361] radeon 0000:01:00.0: GRBM_STATUS = 0xC0003828 [ 3943.499366] radeon 0000:01:00.0: GRBM_STATUS_SE0 = 0x80000007 [ 3943.499371] radeon 0000:01:00.0: GRBM_STATUS_SE1 = 0x00000007 [ 3943.499376] radeon 0000:01:00.0: SRBM_STATUS = 0x20000CC0 [ 3943.499381] radeon 0000:01:00.0: SRBM_STATUS2 = 0x00000000 [ 3943.499386] radeon 0000:01:00.0: R_008674_CP_STALLED_STAT1 = 0x00000000 [ 3943.499392] radeon 0000:01:00.0: R_008678_CP_STALLED_STAT2 = 0x00000000 [ 3943.499397] radeon 0000:01:00.0: R_00867C_CP_BUSY_STAT = 0x00000000 [ 3943.499402] radeon 0000:01:00.0: R_008680_CP_STAT = 0x00000000 [ 3943.499407] radeon 0000:01:00.0: R_00D034_DMA_STATUS_REG = 0x44C83D57 [ 3943.880423] radeon 0000:01:00.0: Wait for MC idle timedout ! [ 3943.880432] radeon 0000:01:00.0: GRBM_SOFT_RESET=0x00007F6A [ 3943.881600] radeon 0000:01:00.0: GRBM_STATUS = 0xC0003828 [ 3943.881603] radeon 0000:01:00.0: GRBM_STATUS_SE0 = 0x80000007 [ 3943.881606] radeon 0000:01:00.0: GRBM_STATUS_SE1 = 0x00000007 [ 3943.881609] radeon 0000:01:00.0: SRBM_STATUS = 0x20000CC0 [ 3943.881612] radeon 0000:01:00.0: SRBM_STATUS2 = 0x00000000 [ 3943.881615] radeon 0000:01:00.0: R_008674_CP_STALLED_STAT1 = 0x00000000 [ 3943.881618] radeon 0000:01:00.0: R_008678_CP_STALLED_STAT2 = 0x00000000 [ 3943.881621] radeon 0000:01:00.0: R_00867C_CP_BUSY_STAT = 0x00000000 [ 3943.881625] radeon 0000:01:00.0: R_008680_CP_STAT = 0x00000000 [ 3943.881628] radeon 0000:01:00.0: R_00D034_DMA_STATUS_REG = 0x44C83D57